Publications

@article{breitenbach_versuche_1963,
title = {{VERSUCHE} {ZUR} {STRAHLUNGSPOLYMERISATION} - {KURZE} {MITTEILUNG}},
volume = {94},
issn = {0026-9247},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=19638381&action=retrieve&mode=FullRecord},
doi = {10.1007/bf00900265},
language = {English},
number = {2},
journal = {Monatshefte fur Chemie},
author = {Breitenbach, J. W. and Wolf, B. and Olaj, O. F.},
year = {1963},
pages = {373--\&},
}
@article{breitenbach_molekulargewichtsverleilung_1964,
title = {Molekulargewichtsverleilung und {Kristallinität} bei n-butyllithiumgestarteten {Polystyrolen}},
volume = {95},
journal = {Monatshefte fur Chemie},
author = {Breitenbach, J. W. and Kratzert, S. and Wolf, Bernhard Anton},
year = {1964},
pages = {508},
}
@article{breitenbach_untersuchungen_1964,
title = {Untersuchungen von {Molekulargewichtsverteilungen} von {Hochpolymeren}, 5. {Mitt}},
volume = {95},
shorttitle = {Untersuchungen von {Molekulargewichtsverteilungen} von {Hochpolymeren}, 5. {Mitt}.},
journal = {Monatshefte fuer Chemie},
author = {Breitenbach, J. W. and Wolf, Bernhard Anton},
year = {1964},
pages = {508},
}
@article{olaj_untersuchungen_1964,
title = {{UNTERSUCHUNGEN} {UBER} {MOLEKULARGEWICHTSVERTEILUNGEN} {VON} {HOCHPOLYMEREN}, 6.{MITT}. - {ZUM} {PROBLEM} {DES} {DISPROPORTIONIERUNGSABBRUCHS} {BEI} {DER} {GESTARTETEN} {POLYMERISATION} {DES} {STYROLS}},
volume = {95},
issn = {0343-7329},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=19646027800027&action=retrieve&mode=FullRecord},
doi = {10.1007/bf00901723},
language = {English},
number = {6},
journal = {Monatshefte Fur Chemie Und Verwandte Teile Anderer Wissenschaften},
author = {Olaj, O. F. and Breitenb. Jw and Wolf, B.},
year = {1964},
pages = {1646--\&},
}
@article{breitenbach_untersuchungen_1967,
title = {{UNTERSUCHUNGEN} {VON} {PHASENGLEICHGEWICHTEN} {AN} {POLYMERLOSUNGEN} {MITTELS} {SAULENFRAKTIONIERUNG}},
volume = {108},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1967&action=retrieve&mode=FullRecord},
language = {English},
number = {OCT},
journal = {Makromolekulare Chemie},
author = {Breitenbach, J. W. and Wolf, B. A.},
year = {1967},
pages = {263--+},
}
@article{wolf_comment_1968,
title = {Comment on {Novel} {Parameter} of {Polymer} {Structure} {Suggested} by {Bahary},{Ws}},
volume = {12},
issn = {0021-8995},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1968&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/app.1968.070120430},
language = {English},
number = {4},
journal = {Journal of Applied Polymer Science},
author = {Wolf, B. A.},
year = {1968},
pages = {973--\&},
}
@article{breitenbach_mutual_1968,
title = {{MUTUAL} {INFLUENCE} {OF} {POLYMERS} {OF} {DIFFERENT} {MOLECULAR} {WEIGHTS} {ON} {SOLUBILITY}},
volume = {117},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1968&action=retrieve&mode=FullRecord},
language = {English},
number = {OCT},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Breitenbach, J. W. and Wolf, B. A.},
year = {1968},
pages = {163--+},
}
@article{wolf_zum_1969,
title = {Zum {Copolymerisationsverhalten} von {Perfluorcyclohexadien}-1,3},
volume = {6},
journal = {Angewandte Makromolekulare Chemie},
author = {Wolf, Bernhard Anton},
year = {1969},
pages = {70--78},
}
@article{wolf_determination_1969,
title = {Determination of {Critical} {Concentration} of {Polymer} {Solutions}},
volume = {128},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1969&action=retrieve&mode=FullRecord},
language = {German},
number = {Oct},
journal = {Makromolekulare Chemie},
author = {Wolf, B. A.},
year = {1969},
pages = {284--287},
}
@article{wolf_experimentelle_1969,
title = {Experimentelle {Möglichkeiten} zur {Bestimmung} von {Molekulargewichtsverteilungen}},
volume = {20},
journal = {Allgemeine praktische Chemie},
author = {Wolf, Bernhard Anton},
year = {1969},
pages = {144},
}
@article{wolf_rontgenkleinwinkeluntersuchungen_1970,
title = {Röntgenkleinwinkeluntersuchungen an {Lösungen} eines {Polystyrolpräparats} mit enger {Molekulargewichtsverteilung}},
volume = {101},
journal = {Monatshefte fur Chemie},
author = {Wolf, Bernhard Anton and Breitenbach, J. W. and Senftl, H.},
year = {1970},
pages = {57},
}
@inproceedings{wolf_light_1970,
title = {Light {Scattering} {Investigation} on the p- and {T}-dependence of the {Thermodynamic} {Properties} of {Polyisobutylene}},
volume = {1},
author = {Wolf, Bernhard Anton},
year = {1970},
pages = {139},
}
@article{durchsch_h_x-ray_1970,
title = {X-{Ray} {Small}-{Angle} {Investigations} on {Solutions} of a {Polystyrene}-{Sample} with a {Narrow} {Molecular} {Weight} {Distribution}},
volume = {101},
issn = {0026-9247},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1970&action=retrieve&mode=FullRecord},
doi = {Doi 10.1007/Bf00911412},
language = {German},
number = {5},
journal = {Monatshefte fur Chemie},
author = {Durchsch. H and Kratky, O. and Breitenb. Jw and Wolf, B. A.},
year = {1970},
pages = {1462--\&},
}
@article{wolf_mutual_1970,
title = {{MUTUAL} {INFLUENCE} {OF} {POLYMERS} {OF} {DIFFERENT} {MOLECULAR} {WEIGHTS} {ON} {SOLUBILITY} .2. {MIXED} {SOLVENT} {SYSTEMS} {WITH} {PREFERENTIAL} {ADSORPTION} {OF} {PRECIPITANT} {BY} {POLYMER}},
volume = {101},
issn = {0026-9247},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1970&action=retrieve&mode=FullRecord},
doi = {10.1007/bf00907525},
language = {German},
number = {1},
journal = {Monatshefte fur Chemie},
author = {Wolf, B. A. and Breitenb. Jw and Senftl, H.},
year = {1970},
pages = {57--\&},
}
@inproceedings{wolf_separation_1971,
series = {Macromolecular {Preprints}},
title = {Separation of {Polymer} {Homologues} on {Demixing} - {Dependence} on the {Type} of {Mixed} {Solvent}},
volume = {1},
author = {Wolf, B. A. and Breitenbach, J. W. and Senftl, H.},
year = {1971},
pages = {520},
}
@article{wolf_scattered_1971,
title = {Scattered {Light} {Studies} on {Exothermic} {Pseudoideal} {Solutions} in {Dependence} on {Pressure} and {Temperature}},
volume = {75},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1971&action=retrieve&mode=FullRecord},
language = {German},
number = {9},
journal = {Berichte Der Bunsen-Gesellschaft Fur Physikalische Chemie},
author = {Wolf, B. A.},
year = {1971},
pages = {924--\&},
}
@article{wolf_interdependence_1972,
title = {Interdependence of {Enthalpic} and {Entropic} {Contributions} to {Second} {Osmotic} {Virial}-{Coefficient}},
volume = {10},
issn = {0449-2978},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1972&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/pol.1972.160100506},
language = {English},
number = {5},
journal = {Journal of Polymer Science Part a-2-Polymer Physics},
author = {Wolf, B. A.},
year = {1972},
pages = {847--\&},
}
@article{wolf_zur_1972,
title = {Zur {Thermodynamik} der enthalpisch und der entropisch bedingten {Entmischung} von {Polymerlösungen}},
volume = {10},
journal = {Advances in Polymer Science},
author = {Wolf, Bernhard Anton},
year = {1972},
pages = {109--171},
}
@article{lechner_thermodynamics_1972,
title = {Thermodynamics of {Polymer}-{Solutions} as {Functions} of {Pressure} and {Temperature}},
volume = {39},
issn = {0021-9797},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1972&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/0021-9797(72)90053-7},
language = {English},
number = {3},
journal = {Journal of Colloid and Interface Science},
author = {Lechner, M. D. and Wolf, B. A. and Schulz, G. V.},
year = {1972},
pages = {462--\&},
}
@article{wolf_sedimentation_1972,
title = {Sedimentation of {Dissolved} {Macromolecules} in {Terrestrial} {Gravitational}-{Field} near {Critical} {Locus}},
volume = {161},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1972&action=retrieve&mode=FullRecord},
language = {English},
number = {Nov},
journal = {Makromolekulare Chemie},
author = {Wolf, B. A.},
year = {1972},
pages = {277--\&},
}
@article{breitenbach_degradation_1973,
title = {Degradation of {Polystyrene} in {Cyclohexane} {Solution} at a {Low} {Shearing} {Rate}},
volume = {164},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1973&action=retrieve&mode=FullRecord},
language = {German},
number = {Feb},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Breitenbach, J. W. and Rigler, J. K. and Wolf, B. A.},
year = {1973},
pages = {353--355},
}
@article{wolf_upper_1973,
title = {Upper {Gaps} of {Mixing} for {Polystyrene} {Solutions} at {Room}-{Temperature}},
volume = {34},
issn = {0003-3146},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1973&action=retrieve&mode=FullRecord},
language = {German},
number = {Dec},
journal = {Angewandte Makromolekulare Chemie},
author = {Wolf, B. A. and Breitenb. Jw and Rigler, J. K.},
year = {1973},
pages = {177--182},
}
@article{wolf_true_1973,
title = {True {Cosolvency} - {Acetone} / {Diethylether} / {Pol}},
volume = {173},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1973&action=retrieve&mode=FullRecord},
language = {English},
number = {Dec7},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Wolf, B. A. and Molinari, R. J.},
year = {1973},
pages = {241--245},
}
@incollection{wolf_polymer-solvent_1975,
address = {New York},
edition = {2nd},
title = {Polymer-{Solvent} {Interaction} {Parameters}},
booktitle = {Polymer {Handbook}},
publisher = {Wiley Interscience},
author = {Wolf, Bernhard Anton},
editor = {Brandrup, J. and Immergut, E. H.},
year = {1975},
}
@article{wolf_measured_1975,
title = {{MEASURED} {AND} {CALCULATED} {SOLUBILITY} {OF} {POLYMERS} {IN} {MIXED} {SOLVENTS} - {MONOTONY} {AND} {COSOLVENCY}},
volume = {13},
issn = {0887-6266},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1975&action=retrieve&mode=FullRecord},
doi = {10.1002/pol.1975.180130605},
language = {English},
number = {6},
journal = {Journal of Polymer Science Part B-Polymer Physics},
author = {Wolf, B. A. and Blaum, G.},
year = {1975},
pages = {1115--1132},
}
@article{wolf_stoffe_1976,
title = {Stoffe und ihre {Umwandlungen}},
journal = {Spektrum der Wissenschaft},
author = {Wolf, Bernhard Anton},
year = {1976},
}
@article{wolf_entdeckung_1976,
title = {Die {Entdeckung} der {Elemente}},
journal = {Spektrum der Wissenschaft},
author = {Wolf, Bernhard Anton},
year = {1976},
}
@article{wolf_geschichte_1976,
title = {Die {Geschichte} der {Chemie}},
journal = {Spektrum der Wissenschaft},
author = {Wolf, Bernhard Anton},
year = {1976},
}
@article{wolf_pressure_1976,
title = {{PRESSURE} {INFLUENCE} {ON} {TRUE} {COSOLVENCY} - {MEASURED} {AND} {CALCULATED} {SOLUBILITY} {LIMITS} {OF} {POLYSTYRENE} {IN} {MIXTURES} {OF} {ACETONE} {AND} {DIETHYLETHER}},
volume = {177},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1976&action=retrieve&mode=FullRecord},
language = {English},
number = {4},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Wolf, B. A. and Blaum, G.},
year = {1976},
pages = {1073--1088},
}
@article{blaum_generation_1976,
title = {Generation of {True} {Cosolvency} by {Pressure} - {Solubility} {Limits} of {High} {Molecular}-{Weight} {Polystyrene} in {Mixtures} of {Acetone} and {Diethyl}-{Ether}},
volume = {9},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1976&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma60052a009},
language = {English},
number = {4},
journal = {Macromolecules},
author = {Blaum, G. and Wolf, B. A.},
year = {1976},
pages = {579--582},
}
@article{wolf_comparison_1976,
title = {{COMPARISON} {OF} {UNPERTURBED} {DIMENSION} {OF} {POLYSTYRENE} {FOR} {ENDOTHERMAL} {AND} {EXOTHERMAL} {HEATS} {OF} {DILUTION} {WITHIN} {SAME} {SYSTEM}},
volume = {17},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1976&action=retrieve&mode=FullRecord},
doi = {10.1016/0032-3861(76)90277-9},
language = {English},
number = {7},
journal = {Polymer},
author = {Wolf, B. A. and Bieringer, H. F. and Breitenbach, J. W.},
year = {1976},
pages = {605--610},
}
@article{rigler_viscosity_1977,
title = {Viscosity of {Polymer}-{Solutions} near by {Upper} and {Lower} {Critical} {Solution} {Temperatures}},
volume = {57},
issn = {0003-3146},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1977&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/apmc.1977.050570102},
language = {German},
number = {Jan25},
journal = {Angewandte Makromolekulare Chemie},
author = {Rigler, J. K. and Wolf, B. A. and Breitenbach, J. W.},
year = {1977},
pages = {15--27},
}
@article{wolf_dependence_1977,
title = {Dependence of {Oligomer}-{Oligomer} {Incompatibility} on {Chain}-{Length} and {Pressure} .1. {Oligo}-{Isobutene}-{Oligo}-{Propylene} {Glycol} and {Oligo}-{Styrene}-{Oligo}-{Ethylene} {Glycol}},
issn = {0360-8905},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1977&action=retrieve&mode=FullRecord},
language = {English},
number = {61},
journal = {Journal of Polymer Science Part C-Polymer Symposium},
author = {Wolf, B. A. and Blaum, G.},
year = {1977},
pages = {251--270},
}
@article{wolf_thermodynamic_1977,
title = {{THERMODYNAMIC} {PROPERTIES} {OF} {LIQUID} {OLIGOMER}-1 {OLIGOMER}-2 {SYSTEMS} - {TRANSITION} {FROM} {MIXTURES} {OF} {LOW}-{MOLECULAR} {WEIGHT} {COMPOUNDS} {TO} {POLYMER}-{SOLUTIONS} {AND} {POLYMER} {MIXTURES}},
volume = {81},
issn = {0005-9021},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1977&action=retrieve&mode=FullRecord},
doi = {10.1002/bbpc.19770811019},
language = {English},
number = {10},
journal = {Berichte Der Bunsen-Gesellschaft-Physical Chemistry Chemical Physics},
author = {Wolf, B. A. and Blaum, G.},
year = {1977},
pages = {991--992},
}
@article{wolf_possibilities_1977,
title = {Possibilities for {Determination} of {Enthalpies} and {Volumes} of {Mixing} from {Molecular}-{Weight} {Dependence} of {Critical} {Demixing} {Temperatures} and {Pressures}, {Demonstrated} for {System} {Trans}-{Decahydronaphthalene}-{Polystyrene}},
volume = {178},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1977&action=retrieve&mode=FullRecord},
language = {German},
number = {6},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Wolf, B. A. and Jend, R.},
year = {1977},
pages = {1811--1822},
}
@article{jend_generation_1977,
title = {The {Generation} of {Polymer} {Incompatibility} by {Variation} of {Chain} {Length} and {Pressure}},
volume = {9},
journal = {High Temperatures - High Pressures},
author = {Jend, R. and Wolf, Bernhard Anton},
year = {1977},
pages = {561},
}
@article{wolf_generation_1977,
title = {{GENERATION} {OF} {POLYMER} {INCOMPATIBILITY} {BY} {VARIATION} {OF} {CHAIN}-{LENGTH} {AND} {PRESSURE}},
volume = {173},
issn = {0065-7727},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1977&action=retrieve&mode=FullRecord},
language = {English},
number = {MAR20},
journal = {Abstracts of Papers of the American Chemical Society},
author = {Wolf, B. A. and Blaum, G.},
year = {1977},
pages = {3--3},
}
@article{wolf_extrapolation_1977,
title = {{EXTRAPOLATION} {METHOD} {FOR} {DETERMINATION} {OF} {SOLUBILITY} {PARAMETERS} {OF} {POLYMERS} {DEMONSTRATED} {FOR} {POLYETHYLENE}},
volume = {178},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1977&action=retrieve&mode=FullRecord},
language = {English},
number = {6},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Wolf, B. A.},
year = {1977},
pages = {1869--1871},
}
@article{wolf_viscometric_1977,
title = {Viscometric {Determination} of {Thermodynamic} {Demixing} {Data} for {Polymer}-{Solutions}},
volume = {10},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1977&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma60059a025},
language = {English},
number = {5},
journal = {Macromolecules},
author = {Wolf, B. A. and Sezen, M. C.},
year = {1977},
pages = {1010--1014},
}
@article{wolf_efficiency_1978,
title = {Efficiency of {Polymer} {Fractionation} at {Lower} {Critical} {Solution} {Temperatures}},
volume = {10},
issn = {0007-1641},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1978&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/pi.4980100211},
language = {English},
number = {2},
journal = {British Polymer Journal},
author = {Wolf, B. A. and Bieringer, H. F. and Breitenbach, J. W.},
year = {1978},
pages = {156--160},
}
@article{wolf_measured_1978,
title = {{MEASURED} {AND} {CALCULATED} {SOLUBILITY} {OF} {POLYMERS} {IN} {MIXED}-{SOLVENTS} - {CO}-{NON}-{SOLVENCY}},
volume = {179},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1978&action=retrieve&mode=FullRecord},
language = {English},
number = {9},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Wolf, B. A. and Willms, M. M.},
year = {1978},
pages = {2265--2277},
}
@article{rigler_interaction_1978,
title = {Interaction {Parameters} in {Some} {Ternary}-{Systems} {Styrene}-{Polystyrene}-{Rubber}},
volume = {74},
issn = {0003-3146},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1978&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/apmc.1978.050740109},
language = {English},
number = {Dec},
journal = {Angewandte Makromolekulare Chemie},
author = {Rigler, J. K. and Muller, L. and Wolf, B. A.},
year = {1978},
pages = {113--122},
}
@article{wolf_pressure_1979,
title = {{PRESSURE} {AND} {TEMPERATURE}-{DEPENDENCE} {OF} {THE} {VISCOSITY} {OF} {POLYMER}-{SOLUTIONS} {IN} {THE} {REGION} {OF} {PHASE}-{SEPARATION}},
volume = {12},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1979&action=retrieve&mode=FullRecord},
doi = {10.1021/ma60070a039},
language = {English},
number = {4},
journal = {Macromolecules},
author = {Wolf, B. A. and Jend, R.},
year = {1979},
pages = {732--737},
}
@article{schmidt_pressure-dependence_1979,
title = {Pressure-{Dependence} of the {Viscosity} of {Polymer}-{Solutions} and {How} {It} {Reflects} the {Thermodynamic} {Conditions}},
volume = {180},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1979&action=retrieve&mode=FullRecord},
language = {English},
number = {2},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Schmidt, J. R. and Wolf, B. A.},
year = {1979},
pages = {517--521},
}
@article{wolf_oligomer-oligomer_1979,
title = {Oligomer-{Oligomer} {Incompatibility} .2. {Oligo}({Dimethylsiloxane})-{Oligo}({Propylene} {Glycol})},
volume = {180},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1979&action=retrieve&mode=FullRecord},
language = {English},
number = {11},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Wolf, B. A. and Blaum, G.},
year = {1979},
pages = {2591--2603},
}
@article{wolf_oligomer-oligomer_1981,
title = {{OLIGOMER}-{OLIGOMER} {INCOMPATIBILITY} .3. {END}-{GROUP} {EFFECTS}},
volume = {182},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1981&action=retrieve&mode=FullRecord},
language = {English},
number = {6},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Wolf, B. A. and Schuch, W.},
year = {1981},
pages = {1801--1818},
}
@inproceedings{gleixner_solubility_1979,
title = {The solubility of barium polystyrene sulfonate in water as a function of pressure, temperarure and molecular weight},
author = {Gleixner, G. and Wolf, Bernhard Anton},
year = {1979},
pages = {896 Preprints II},
}
@inproceedings{ballauff_sedimentation_1979,
title = {Sedimentation of dissolved macromolecules in the terrestrial gravitatinal field near the critical locus},
author = {Ballauff, M. and Wolf, Bernhard Anton},
year = {1979},
}
@article{schmidt_demixing_1979,
title = {Demixing of {Unsheared} and {Sheared} {Solutions} of {Polystyrene} in {Tert}-{Butylacetate} and the {Pressure} {Influence} on {Their} {Flow} {Behavior}},
volume = {257},
issn = {0303-402X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1979&action=retrieve&mode=FullRecord},
doi = {Doi 10.1007/Bf01517243},
language = {English},
number = {11},
journal = {Colloid and Polymer Science},
author = {Schmidt, J. R. and Wolf, B. A.},
year = {1979},
pages = {1188--1195},
}
@article{wolf_theoretical_1980,
title = {Theoretical {Description} of {Phase}-{Separation} in {Flowing} {Polymer}-{Solutions}},
volume = {1},
issn = {0173-2803},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1980&action=retrieve&mode=FullRecord},
language = {English},
number = {4},
journal = {Makromolekulare Chemie-Rapid Communications},
author = {Wolf, B. A.},
year = {1980},
pages = {231--234},
}
@article{wolf_phase-separation_1980,
title = {Phase-{Separation} of {Flowing} {Polymer}-{Solutions} {Studied} by {Viscosity} and by {Turbidity}},
volume = {18},
issn = {0887-6258},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1980&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/pol.1980.130181207},
language = {English},
number = {12},
journal = {Journal of Polymer Science Part C-Polymer Letters},
author = {Wolf, B. A. and Kramer, H.},
year = {1980},
pages = {789--794},
}
@article{ballauff_degradation_1981,
title = {Degradation of {Chain} {Molecules} .1. {Exact} {Solution} of the {Kinetic}-{Equations}},
volume = {14},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1981&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma50004a039},
language = {English},
number = {3},
journal = {Macromolecules},
author = {Ballauff, M. and Wolf, B. A.},
year = {1981},
pages = {654--658},
}
@article{wolf_2nd_1981,
title = {2nd {Osmotic} {Virial}-{Coefficient} {Revisited} - {Variation} with {Molecular}-{Weight} and {Temperature} from {Endothermal} to {Exothermal} {Conditions}},
volume = {75},
issn = {0021-9606},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1981&action=retrieve&mode=FullRecord},
doi = {Doi 10.1063/1.442500},
language = {English},
number = {8},
journal = {Journal of Chemical Physics},
author = {Wolf, B. A. and Adam, H. J.},
year = {1981},
pages = {4121--4129},
}
@article{geerissen_factors_1982,
title = {On the {Factors} {Governing} the {Pressure}-{Dependence} of the {Viscosity} of {Moderately} {Concentrated} {Polymer}-{Solutions}},
volume = {27},
issn = {0021-8995},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1982&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/app.1982.070270417},
language = {English},
number = {4},
journal = {Journal of Applied Polymer Science},
author = {Geerissen, H. and Schmidt, J. R. and Wolf, B. A.},
year = {1982},
pages = {1277--1291},
}
@inproceedings{ballauff_slowing_1981,
title = {Slowing down of segmental mobolity of dissolved polymers near the consolute point, studied by shear degradation},
volume = {II},
author = {Ballauff, M. and Wolf, Bernhard Anton},
year = {1981},
pages = {659},
}
@article{wolf_pressure-dependence_1981,
title = {{PRESSURE}-{DEPENDENCE} {OF} {THE} {DEMIXING} {OF} {POLYMER}-{SOLUTIONS} {DETERMINED} {BY} {VISCOMETRY}},
volume = {259},
issn = {0303-402X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1981&action=retrieve&mode=FullRecord},
doi = {10.1007/bf01525017},
language = {English},
number = {12},
journal = {Colloid and Polymer Science},
author = {Wolf, B. A. and Geerissen, H.},
year = {1981},
pages = {1214--1220},
}
@article{geerissen_phenylalkanes_1982,
title = {Phenylalkanes as {Theta}-{Solvents} for {Polystyrene}},
volume = {3},
issn = {0173-2803},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1982&action=retrieve&mode=FullRecord},
language = {English},
number = {1},
journal = {Makromolekulare Chemie-Rapid Communications},
author = {Geerissen, H. and Wolf, B. A.},
year = {1982},
pages = {17--21},
}
@article{ballauff_rheological_1983,
title = {Rheological {Studies} of {Moderately} {Concentrated} {Polystyrene} {Solutions} .1. {A} {New} {Method} for the {Extrapolation} of the {Zero}-{Shear} {Viscosity}},
volume = {21},
issn = {0887-6266},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1983&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/pol.1983.180210719},
language = {English},
number = {7},
journal = {Journal of Polymer Science Part B-Polymer Physics},
author = {Ballauff, M. and Kramer, H. and Wolf, B. A.},
year = {1983},
pages = {1205--1216},
}
@article{ballauff_rheological_1983-1,
title = {Rheological {Studies} of {Moderately} {Concentrated} {Polystyrene} {Solutions} in the {Vicinity} of the {Theta}-{Temperature} .2. {Shear}-{Rate} {Dependence} for {Different} {Thermodynamic} {Conditions}},
volume = {21},
issn = {0887-6266},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1983&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/pol.1983.180210720},
language = {English},
number = {7},
journal = {Journal of Polymer Science Part B-Polymer Physics},
author = {Ballauff, M. and Kramer, H. and Wolf, B. A.},
year = {1983},
pages = {1217--1226},
}
@incollection{wolf_interrelation_1983,
edition = {1st},
title = {Interrelation of rheological and thermodynamic solution properties},
booktitle = {Polymer {Yearbook}},
publisher = {Harwood Acad. Publ.},
author = {Wolf, Bernhard Anton},
editor = {Elias, H. G. and Pethrick, R. A.},
year = {1983},
pages = {269},
}
@article{schmidt_pressure-dependence_1982,
title = {Pressure-{Dependence} of {Intrinsic} {Viscosities} and {Huggins} {Constants} for {Polystyrene} in {Tert}-{Butyl} {Acetate}},
volume = {15},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1982&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00232a046},
language = {English},
number = {4},
journal = {Macromolecules},
author = {Schmidt, J. R. and Wolf, B. A.},
year = {1982},
pages = {1192--1195},
}
@article{wolf_pressure_1982,
title = {Pressure {Influences} on the {Viscosity} of {Polymer}-{Solutions}},
volume = {21},
issn = {0035-4511},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1982&action=retrieve&mode=FullRecord},
doi = {Doi 10.1007/Bf01534331},
language = {English},
number = {4-5},
journal = {Rheologica Acta},
author = {Wolf, B. A. and Geerissen, H. and Jend, R. and Schmidt, J. R.},
year = {1982},
pages = {505--507},
}
@patent{wolf_verfahren_nodate,
address = {Deutschland},
title = {Verfahren zur kontinuierlichen {Fraktionierung} von {Polymeren} im technischen {Maßstab}},
nationality = {C08F006-04},
language = {German},
assignee = {Mehrere natuerliche Personen},
number = {DE3242130.3A1},
author = {Wolf, Bernhard Anton and Geerissen, Heinz and Roos, J. and Amareshwar, P.},
pages = {Textseiten 17; Zeichnungsseiten 5},
}
@article{schulz_solution_1983,
title = {Solution {Properties} of {Poly}({Decylmethacrylate}){S}},
volume = {8},
issn = {0254-0584},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1983&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/0254-0584(83)90036-6},
language = {English},
number = {3},
journal = {Materials Chemistry and Physics},
author = {Schulz, G. V. and Haug, A.},
year = {1983},
pages = {243--250},
}
@article{maderek_high-temperature_1983,
title = {High-{Temperature} {Demixing} of {Poly}({Decyl} {Methacrylate}) {Solutions} in {Isooctane} and {Its} {Pressure}-{Dependence}},
volume = {184},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1983&action=retrieve&mode=FullRecord},
language = {English},
number = {6},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Maderek, E. and Schulz, G. V. and Wolf, B. A.},
year = {1983},
pages = {1303--1309},
}
@article{maderek_lower_1983,
title = {Lower {Critical} {Solution} {Temperatures} of {Poly}({Decyl} {Methacrylate}) in {Hydrocarbons}},
volume = {19},
issn = {0014-3057},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1983&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/0014-3057(83)90057-5},
language = {English},
number = {10-1},
journal = {European Polymer Journal},
author = {Maderek, E. and Schulz, G. V. and Wolf, B. A.},
year = {1983},
pages = {963--965},
}
@article{herold_non-newtonian_1983,
title = {Non-{Newtonian} {Flow} {Behavior} of {Poly}({Decyl} {Methacrylate}) {Solutions}},
volume = {184},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1983&action=retrieve&mode=FullRecord},
language = {English},
number = {12},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Herold, F. K. and Wolf, B. A.},
year = {1983},
pages = {2539--2551},
}
@article{wolf_thermodynamic_1984,
title = {Thermodynamic {Theory} of {Flowing} {Polymer}-{Solutions} and {Its} {Application} to {Phase}-{Separation}},
volume = {17},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1984&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00134a017},
language = {English},
number = {4},
journal = {Macromolecules},
author = {Wolf, B. A.},
year = {1984},
pages = {615--618},
}
@article{maderek_detection_1983,
title = {Detection of the {Liquid} {Liquid} {Demixing} by {Differential} {Scanning} {Calorimetry}},
volume = {10},
issn = {0170-0839},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1983&action=retrieve&mode=FullRecord},
doi = {Doi 10.1007/Bf00262190},
language = {English},
number = {9-10},
journal = {Polymer Bulletin},
author = {Maderek, E. and Wolf, B. A.},
year = {1983},
pages = {458--463},
}
@article{schotsch_excess_1984,
title = {Excess {Volumes} of ({Tert}-{Butyl} {Chloride} + {Tetrachloromethane}) and of ({Cyclohexane} + 1,3-{Diphenylbutane})},
volume = {16},
issn = {0021-9614},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1984&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/0021-9614(84)90014-4},
language = {English},
number = {6},
journal = {Journal of Chemical Thermodynamics},
author = {Schotsch, K. and Wolf, B. A.},
year = {1984},
pages = {601--602},
}
@article{schotsch_vapor-pressures_1984,
title = {Vapor-{Pressures} of the {System} {Tert}-{Butyl} {Acetate} {Polystyrene}},
volume = {185},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1984&action=retrieve&mode=FullRecord},
language = {English},
number = {10},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Schotsch, K. and Wolf, B. A.},
year = {1984},
pages = {2161--2167},
}
@article{schotsch_concentration-dependence_1984,
title = {Concentration-{Dependence} of the {Flory}-{Huggins} {Parameter} at {Different} {Thermodynamic} {Conditions}},
volume = {185},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1984&action=retrieve&mode=FullRecord},
language = {English},
number = {10},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Schotsch, K. and Wolf, B. A. and Jeberien, H. E. and Klein, J.},
year = {1984},
pages = {2169--2181},
}
@article{wolf_solubility_1985,
title = {Solubility of {Polymers}},
volume = {57},
issn = {0033-4545},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1985&action=retrieve&mode=FullRecord},
doi = {DOI 10.1351/pac198557020323},
language = {English},
number = {2},
journal = {Pure and Applied Chemistry},
author = {Wolf, B. A.},
year = {1985},
pages = {323--336},
}
@article{geerissen_continuous_1985,
title = {Continuous {Fractionation} and {Solution} {Properties} of {Pvc} .1. {Continuous} {Fractionation}, {Characterization}},
volume = {186},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1985&action=retrieve&mode=FullRecord},
language = {English},
number = {4},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Geerissen, H. and Roos, J. and Wolf, B. A.},
year = {1985},
pages = {735--751},
}
@article{geerissen_continuous_1985-1,
title = {Continuous {Fractionation} and {Solution} {Properties} of {Pvc} .2. {Scrutiny} of {Solvents}, {Intrinsic}-{Viscosity}},
volume = {186},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1985&action=retrieve&mode=FullRecord},
language = {English},
number = {4},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Geerissen, H. and Roos, J. and Wolf, B. A.},
year = {1985},
pages = {753--767},
}
@article{geerissen_continuous_1985-2,
title = {Continuous {Fractionation} and {Solution} {Properties} of {Pvc} .3. {Pressure}-{Dependence} of the {Solubility} in {Single} {Solvents}},
volume = {186},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1985&action=retrieve&mode=FullRecord},
language = {English},
number = {4},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Geerissen, H. and Roos, J. and Wolf, B. A.},
year = {1985},
pages = {769--776},
}
@article{geerissen_continuous_1985-3,
title = {Continuous {Fractionation} and {Solution} {Properties} of {Pvc} .4. {Pressure}-{Dependence} of the {Solubility} in a {Mixed}-{Solvent}},
volume = {186},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1985&action=retrieve&mode=FullRecord},
language = {English},
number = {4},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Geerissen, H. and Roos, J. and Wolf, B. A.},
year = {1985},
pages = {777--785},
}
@article{geerissen_continuous_1985-4,
title = {Continuous {Fractionation} and {Solution} {Properties} of {Pvc} .5. {Pressure}-{Dependence} of the {Viscosity} - {Influence} of {Solvent}},
volume = {186},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1985&action=retrieve&mode=FullRecord},
language = {English},
number = {4},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Geerissen, H. and Roos, J. and Wolf, B. A.},
year = {1985},
pages = {787--799},
}
@article{geerissen_continuous_1985-5,
title = {Continuous {Fractionation} and {Solution} {Properties} of {Pvc} .6. {Pressure}-{Dependence} of the {Viscosity} - {Influence} of {Molecular}-{Weight} and {Composition}},
volume = {186},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1985&action=retrieve&mode=FullRecord},
language = {English},
number = {4},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Geerissen, H. and Roos, J. and Wolf, B. A.},
year = {1985},
pages = {801--815},
}
@article{kramer_occurrence_1985,
title = {{ON} {THE} {OCCURRENCE} {OF} {SHEAR}-{INDUCED} {DISSOLUTION} {AND} {SHEAR}-{INDUCED} {DEMIXING} {WITHIN} {ONE} {AND} {THE} {SAME} {POLYMER} {SOLVENT} {SYSTEM}},
volume = {6},
issn = {0173-2803},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1985&action=retrieve&mode=FullRecord},
language = {English},
number = {1},
journal = {Makromolekulare Chemie-Rapid Communications},
author = {Kramer, H. and Wolf, B. A.},
year = {1985},
pages = {21--27},
}
@article{wolf_2nd_1985,
title = {2nd {Osmotic} {Virial}-{Coefficient} {Revisited} .2. {Buildup} from {Contributions} of {Intermolecular} and {Intramolecular} {Contacts} between {Polymer} {Segments}},
volume = {18},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1985&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00154a022},
language = {English},
number = {12},
journal = {Macromolecules},
author = {Wolf, B. A.},
month = dec,
year = {1985},
pages = {2474--2478},
}
@incollection{geerissen_cpf_1986,
address = {London \& New York},
title = {{CPF}: {A} {New} {Method} for {Large} {Scale} {Fractionation}},
booktitle = {Integration of {Fundamental} {Polymer} {Science} and {Technology}},
publisher = {Elsevier Applied Science},
author = {Geerissen, Heinz and Roos, J. and Wolf, Bernhard Anton},
editor = {Kleintjens, L. A. and Lemstra, P.},
year = {1986},
pages = {99},
}
@article{ballauff_sedimentation_1986,
title = {Sedimentation of {Dissolved} {Macromolecules} in the {Vicinity} of the {Consolute} {Point} .1. {Strictly} {Binary}-{Systems} and {Kinetic} {Considerations}},
volume = {264},
issn = {0303-402X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1986&action=retrieve&mode=FullRecord},
doi = {Doi 10.1007/Bf01414954},
language = {English},
number = {3},
journal = {Colloid and Polymer Science},
author = {Ballauff, M. and Wolf, B. A.},
month = mar,
year = {1986},
pages = {204--211},
}
@article{herold_degradation_1986,
title = {Degradation of {Chain} {Molecules} .3. {The} {Role} of the {Length} of the {Alkyl}-{Groups} in the {Thermodynamically} {Induced} {Shear} {Degradation} of {Dissolved} {Poly}({Normal}-{Alkylmethacrylate}){S}},
volume = {27},
issn = {0263-6476},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1986&action=retrieve&mode=FullRecord},
language = {English},
number = {2},
journal = {Polymer Communications},
author = {Herold, F. K. and Schulz, G. V. and Wolf, B. A.},
month = feb,
year = {1986},
pages = {59--63},
}
@article{herold_polyn-alkylmethacrylates_1986,
title = {Poly({N}-{Alkylmethacrylate}){S} - {Characterization}, {Good} and {Poor} {Solvents}, {Densities} and {Intrinsic} {Viscosities}},
volume = {14},
issn = {0254-0584},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1986&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/0254-0584(86)90068-4},
language = {English},
number = {4},
journal = {Materials Chemistry and Physics},
author = {Herold, F. K. and Wolf, B. A.},
month = apr,
year = {1986},
pages = {311--338},
}
@incollection{gundert_polymer-solvent_1989,
address = {New York},
edition = {3rd},
title = {Polymer-{Solvent} {Interaction} {Parameters}},
booktitle = {Polymer {Handbook}},
publisher = {Wiley Interscience},
author = {Gundert, F. and Wolf, Bernhard Anton},
editor = {Brandrup, J. and Immergut, E. H.},
year = {1989},
pages = {VII/173--182},
}
@article{sander_solubility_1986,
title = {Solubility of {Poly}({Normal}-{Alkylmethacrylate}){S} in {Hydrocarbons} and in {Alcohols}},
volume = {139},
issn = {0003-3146},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1986&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/apmc.1986.051390114},
language = {English},
journal = {Angewandte Makromolekulare Chemie},
author = {Sander, U. and Wolf, B. A.},
month = mar,
year = {1986},
pages = {149--156},
}
@article{cantow_temperature_1987,
title = {Temperature and {Pressure}-{Dependence} of the {Viscosities} of {Perfluoropolyether} {Fluids}},
volume = {25},
issn = {0887-6266},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1987&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/polb.1987.090250311},
language = {English},
number = {3},
journal = {Journal of Polymer Science Part B-Polymer Physics},
author = {Cantow, M. J. R. and Barrall, E. M. and Wolf, B. A. and Geerissen, H.},
month = mar,
year = {1987},
pages = {603--609},
}
@article{wolf_cpf_1986,
title = {{CPF}: {Ein} neues {Verfahren} zur {Fraktionierung} von {Polymeren}},
journal = {Forschungsmagazin der Johannes Gutenberg-Universität Mainz},
author = {Wolf, Bernhard Anton and Geerissen, Heinz and Schützeichel, Peter},
month = apr,
year = {1986},
pages = {89},
}
@article{gundert_2nd_1986,
title = {2nd {Virial}-{Coefficient} {Revisited} .3. {Viscosity} of {Dilute} {Polymer}-{Solutions} - {Molecular}-{Weight} {Dependence} of the {Huggins} {Coefficient}},
volume = {187},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1986&action=retrieve&mode=FullRecord},
language = {English},
number = {12},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Gundert, F. and Wolf, B. A.},
month = dec,
year = {1986},
pages = {2969--2990},
}
@article{geerissen_kapillarviskosimeter_1986,
title = {Ein {Kapillarviskosimeter} für hohe {Temperaturen} zum {Einbau} in kommerzielle {Viskositätsmeßgeräte}},
volume = {30},
journal = {Fachzeitschrift für das Laboratorium},
author = {Geerissen, Heinz and Schützeichel, Peter and Wolf, Bernhard Anton},
year = {1986},
pages = {779},
}
@inproceedings{geerissen_cpf_1986-1,
title = {{CPF}: {Continous} polymer fractionation},
volume = {III},
author = {Geerissen, Heinz and Schützeichel, Peter and Wolf, Bernhard Anton},
year = {1986},
pages = {807},
}
@article{geerissen_continuous_1987,
title = {{CONTINUOUS} {FRACTIONATION} {AND} {SOLUTION} {PROPERTIES} {OF} {PIB} .1. {SEARCH} {FOR} {THE} {BEST} {MIXED}-{SOLVENT} {AND} {1ST} {RESULTS} {OF} {THE} {CONTINUOUS} {POLYMER} {FRACTIONATION}},
volume = {34},
issn = {0021-8995},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1987&action=retrieve&mode=FullRecord},
doi = {10.1002/app.1987.070340123},
language = {English},
number = {1},
journal = {Journal of Applied Polymer Science},
author = {Geerissen, H. and Roos, J. and Schutzeichel, P. and Wolf, B. A.},
month = jul,
year = {1987},
pages = {271--285},
}
@article{geerissen_continuous_1987-1,
title = {{CONTINUOUS} {FRACTIONATION} {AND} {SOLUTION} {PROPERTIES} {OF} {PIB} .2. {CPF} {OPTIMIZATION}},
volume = {34},
issn = {0021-8995},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1987&action=retrieve&mode=FullRecord},
doi = {10.1002/app.1987.070340124},
language = {English},
number = {1},
journal = {Journal of Applied Polymer Science},
author = {Geerissen, H. and Schutzeichel, P. and Wolf, B. A.},
month = jul,
year = {1987},
pages = {287--305},
}
@article{jelich_cooccurrence_1987,
title = {On the {Cooccurrence} of {Demixing} and {Thermoreversible} {Gelation} of {Polymer}-{Solutions} .1. {Experimental}-{Observations}},
volume = {20},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1987&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00174a042},
language = {English},
number = {8},
journal = {Macromolecules},
author = {Jelich, L. M. and Nunes, S. P. and Paul, E. and Wolf, B. A.},
month = aug,
year = {1987},
pages = {1943--1947},
}
@article{nunes_cooccurrence_1987,
title = {On the {Cooccurrence} of {Demixing} and {Thermoreversible} {Gelation} of {Polymer}-{Solutions} .2. {Thermodynamic} {Background}},
volume = {20},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1987&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00174a043},
language = {English},
number = {8},
journal = {Macromolecules},
author = {Nunes, S. P. and Wolf, B. A. and Jeberien, H. E.},
month = aug,
year = {1987},
pages = {1948--1951},
}
@article{nunes_cooccurrence_1987-1,
title = {On the {Cooccurrence} of {Demixing} and {Thermoreversible} {Gelation} of {Polymer}-{Solutions} .3. {Overall} {View}},
volume = {20},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1987&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00174a044},
language = {English},
number = {8},
journal = {Macromolecules},
author = {Nunes, S. P. and Wolf, B. A.},
month = aug,
year = {1987},
pages = {1952--1957},
}
@incollection{wolf_thermodynamically_1989,
address = {Lancaster, Basel},
title = {Thermodynamically induced shear degradation of dissolved polymers},
volume = {II},
booktitle = {Advances in the {Stabilazation} and {Controlled} {Degradation} of {Polymers}},
publisher = {Technomic Publ. Co.},
author = {Wolf, Bernhard Anton and Ballauff, M. and Herold, F. K.},
editor = {Patsis, A. V.},
year = {1989},
pages = {99--104},
}
@article{gundert_molecular-weight_1987,
title = {On the {Molecular}-{Weight} {Dependence} of the {Thermodynamic} and of the {Hydrodynamic} {Pair} {Interaction} between {Chain} {Molecules} .4. 2nd {Virial}-{Coefficients} {Revisited}},
volume = {87},
issn = {0021-9606},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1987&action=retrieve&mode=FullRecord},
doi = {Doi 10.1063/1.453491},
language = {English},
number = {10},
journal = {Journal of Chemical Physics},
author = {Gundert, F. and Wolf, B. A.},
month = nov,
year = {1987},
pages = {6156--6165},
}
@article{wolf_mechanisms_1987,
title = {On the {Mechanisms} of {Polymer} {Degradation} by {Laminar} {Shear}},
volume = {8},
issn = {0173-2803},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1987&action=retrieve&mode=FullRecord},
language = {English},
number = {9},
journal = {Makromolekulare Chemie-Rapid Communications},
author = {Wolf, B. A.},
month = sep,
year = {1987},
pages = {461--466},
}
@patent{baade_losungspolymerisation_nodate,
address = {Deutschland},
title = {Lösungspolymerisation zur {Herstellung} von gelfreien {Ethylen}/{Vinylacetat} {Copolymerisaten}},
abstract = {Hochmolekulare gelfreie Ethylen/Vinylacetat-Copolymerisate lassen sich nach dem Verfahren der Loesungspolymerisation herstellen, wenn ein besonderer Temperatur/Druck-Zusammenhang beachtet wird.},
nationality = {C08F210-02},
language = {German},
assignee = {Bayer AG (*DE 5090 Leverkusen)},
number = {DE 3815946 A1},
author = {Baade, W. and Casper, Rudolf and Meurer, P. and Obrecht, W. and Sylvester, G. and Will, B. and Wolf, B. A. and Zimmerman, H.},
pages = {Textseiten 16; Blattzahl 9; Filmlochkarten 3},
}
@article{ballauff_thermodynamically_1988,
title = {Thermodynamically {Induced} {Shear} {Degradation}},
volume = {85},
issn = {0065-3195},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1988&action=retrieve&mode=FullRecord},
language = {English},
journal = {Advances in Polymer Science},
author = {Ballauff, M. and Wolf, B. A.},
year = {1988},
pages = {1--31},
}
@article{maderek_viscosity-index_1988,
title = {Viscosity-{Index} and {Polymer} {Rheology} - {Comparison} of {Concepts} by {Means} of {Experiments} with {Some} of the {Technically} {Most} {Important} {Systems}},
volume = {161},
issn = {0003-3146},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1988&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/apmc.1988.051610115},
language = {English},
journal = {Angewandte Makromolekulare Chemie},
author = {Maderek, E. and Wolf, B. A.},
month = jul,
year = {1988},
pages = {157--173},
}
@article{will_phase_1988,
title = {Phase separation behavior of the quarternary system ethylene/vinylacetate/tert-butanol/{EVA} (copolymers of ethylene and vinylacetate)},
journal = {Bayer Berichte},
author = {Will, B. and Wolf, Bernhard Anton},
year = {1988},
}
@incollection{koningsveld_fractionation_1989,
address = {Oxford, New York, Seoul, Tokyo},
title = {Fractionation},
booktitle = {Comprehensive {Polymer} {Science}},
publisher = {Pergamon Press},
author = {Koningsveld, R. and Kleintjens, L. and Geerissen, Heinz and Schützeichel, Peter and Wolf, Bernhard Anton},
editor = {G, Allen},
year = {1989},
pages = {239--313},
}
@article{schott_thermodynamics_1988,
title = {Thermodynamics and {High}-{Pressure} {Viscosity} of {Dilute}-{Solutions} of {Poly}({Decyl} {Methacrylate}) and {How} the {Free}-{Volume} {Influences} {Them}},
volume = {189},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1988&action=retrieve&mode=FullRecord},
language = {English},
number = {9},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Schott, N. and Will, B. and Wolf, B. A.},
month = sep,
year = {1988},
pages = {2067--2075},
}
@article{kramer-lucas_influence_1988,
title = {Influence of {Shear} on the {Demixing} of {Polymer}-{Solutions} .1. {Apparatus} and {Experimental} {Results}},
volume = {189},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1988&action=retrieve&mode=FullRecord},
language = {English},
number = {7},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Krämer-Lucas, H. and Schenck, H. and Wolf, B. A.},
month = jul,
year = {1988},
pages = {1613--1625},
}
@article{kramer-lucas_influence_1988-1,
title = {Influence of {Shear} on the {Demixing} of {Polymer}-{Solutions} .2. {Stored} {Energy} and {Theoretical} {Calculations}},
volume = {189},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1988&action=retrieve&mode=FullRecord},
language = {English},
number = {7},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Krämer-Lucas, H. and Schenck, H. and Wolf, B. A.},
month = jul,
year = {1988},
pages = {1627--1634},
}
@article{wolf_pvt_1989,
title = {Pvt {Data} of {Poly}({Perfluoro} {Ether}){S} and {How} {They} {Govern} the {Flow} {Behavior}},
volume = {93},
issn = {0022-3654},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1989&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/J100343a084},
language = {English},
number = {6},
journal = {Journal of Physical Chemistry},
author = {Wolf, B. A. and Klimiuk, M. and Cantow, M. J. R.},
month = mar,
year = {1989},
pages = {2672--2675},
}
@incollection{wolf_thermodynamics_1991,
address = {Weinheim},
title = {Thermodynamics and rheology of polymer solutions},
booktitle = {Chemistry and {Physics} of {Macromolecules}},
publisher = {VCH-Verlag},
author = {Wolf, Bernhard Anton},
editor = {Fischer, E. W. and Schulz, R. C. and Sillescu, H.},
year = {1991},
pages = {273--294},
}
@article{heinrich_kinetics_1990,
title = {Kinetics of {Phase}-{Separation} - {Trapping} of {Molecules} in {Nonequilibrium} {Phases}},
volume = {23},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1990&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00204a035},
language = {English},
number = {2},
journal = {Macromolecules},
author = {Heinrich, M. and Wolf, B. A.},
month = jan,
year = {1990},
pages = {590--596},
}
@article{horst_space_1990,
title = {Space {Filling} and {Flow} {Behavior}},
volume = {94},
issn = {0022-3654},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1990&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/J100380a067},
language = {English},
number = {17},
journal = {Journal of Physical Chemistry},
author = {Horst, R. and Wolf, B. A.},
month = aug,
year = {1990},
pages = {6904--6907},
}
@article{geerissen_large-scale_1990,
title = {{LARGE}-{SCALE} {FRACTIONATION} {OF} {POLYETHYLENE} {BY} {MEANS} {OF} {THE} {CONTINUOUS} {POLYMER} {FRACTIONATION} ({CPF}) {METHOD}},
volume = {191},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1990&action=retrieve&mode=FullRecord},
language = {English},
number = {3},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Geerissen, H. and Schutzeichel, P. and Wolf, B. A.},
month = mar,
year = {1990},
pages = {659--670},
}
@article{geerissen_2nd_1991,
title = {2nd {Virial}-{Coefficients} {Revisited} .5. {Generalization} of the {Concept} of {Intramolecular} {Contributions} to {Low}-{Molecular}-{Weight} {Polymers}},
volume = {24},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1991&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00001a046},
abstract = {In the preceding papers of this series, it has been shown theoretically and experimentally how the Flory-Huggins interaction parameter-chi and the Huggins coefficient k(H) for polymers differing in molecular weight can be built up from the contributions of inter- and intramolecular contacts between polymer segments. The present work reports on measurements with the system isooctane/polyisobutylene (M ranging from 5 to 1350 kg/mol) particularly performed to extend the molecular weight range to lower values. The evaluation of the obtained data according to the equations following from the concept of intramolecular contributions yields two intersecting straight lines instead of one, for A2 as well as for k(H): In the lower molecular weight region the measured values become up to twice as large as that predicted theoretically. It is demonstrated that the reason for this behavior lies in the fact that triples of segments become important upon the reduction of the molecular weight, even if the polymer concentration remains so low that it is only necessary to consider pairs of polymer molecules. Taking this feature into consideration, we formulate a generalized theoretical equation that is able to describe the observed behavior in the entire range of molecular weights.},
language = {English},
number = {1},
journal = {Macromolecules},
author = {Geerissen, H. and Schutzeichel, P. and Wolf, B. A.},
month = jan,
year = {1991},
keywords = {continuous fractionation, dependence, pib},
pages = {304--309},
}
@article{horst_calculation_1991,
title = {{CALCULATION} {OF} {SHEAR} {INFLUENCES} {ON} {THE} {PHASE}-{SEPARATION} {BEHAVIOR} {OF} {POLYMER}-{SOLUTIONS} {IN} {THE} {REGION} {OF} {THEIR} {LOWER} {CRITICAL} {SOLUTION} {TEMPERATURE} - {CREATION} {OF} {CLOSED} {MISCIBILITY} {GAPS}},
volume = {24},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1991&action=retrieve&mode=FullRecord},
doi = {10.1021/ma00009a018},
abstract = {Model calculations concerning the phase separation of sheared solutions were performed for a system with an exothermal theta temperature of 333.3 K and 5000 polymer segments per chain. To determine the demixing conditions for a certain shear rate gamma, a generalized Gibbs energy G-gamma = G(z) + E(s) was used. The Flory-Huggins equation, with a concentration- and temperature-dependent interaction parameter, served as an analytical expression for G(z), the Gibbs energy of mixing at zero shear. E(s), the energy that can be stored during stationary flow, as a function of composition, temperature, and gamma was represented by typical empirical relations. The results of these calculations yield two peculiarities, which are typical for lower critical solution temperatures: (i) At some compositions a temperature interval of homogeneity separates the equilibrium solubility gap from a flow-induced region of immiscibility (bananalike extension of the equilibrium two phase area); this phenomenon is in accord with measurements reported in the literature. (ii) Under very special conditions the above-mentioned extension breaks away from the main heterogeneous region so that a closed miscibility gap is created; this prediction has so far not been verified experimentally.},
language = {English},
number = {9},
journal = {Macromolecules},
author = {Horst, R. and Wolf, B. A.},
month = apr,
year = {1991},
keywords = {dependence, blend, flow, polystyrene, polyvinyl methyl-ether), pressure, system},
pages = {2236--2239},
}
@article{brostow_chain_1991,
title = {Chain {Overlap} and {Intersegmental} {Interactions} in {Polymer}-{Solutions}},
volume = {32},
issn = {0263-6476},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1991&action=retrieve&mode=FullRecord},
abstract = {A combinatorial analysis of solution structure is presented and kinetics of the polymer dissolution process considered. Equations relating the extent of chain overlap to polymer concentration c are derived. The relations allow better management of solution processing of polymeric materials as well as improved drag reduction. Current definitions of the critical concentration c separating dilute solutions from semidilute ones are examined. We find that overlap does occur at c values distinctly lower than c. As a corollary, regions in solution which do not contain any polymer chains occur also when c {\textgreater} c*. A number of experimental findings reported in the literature can now be explained.},
language = {English},
number = {18},
journal = {Polymer Communications},
author = {Brostow, W. and Wolf, B. A.},
year = {1991},
keywords = {angle-neutron-scattering, chain overlap, dilute polymer, drag reduction, elongational flow, good solvents, liquid flow, liquid-crystalline polymers, macromolecular conformations, mechanical degradation, mesogenic sidegroups, molecular-weight dependence, polymer solution processing, polymer solutions, polystyrene solutions, solution structure},
pages = {551--554},
}
@incollection{wolf_phase_1991,
address = {Berlin},
series = {Lecture {Notes} in {Physics}},
title = {Phase {Separation} of {Flowing} {Polymer} {Solutions}},
number = {381},
booktitle = {Rheological {Modelling}: {Thermodynamical} and {Statistical} {Approaches}},
publisher = {Springer-Verlag},
author = {Wolf, Bernhard Anton},
editor = {Casas, Vázquez and Jou, D.},
year = {1991},
pages = {194--214},
}
@article{horst_thermodynamics_1991,
title = {Thermodynamics of {Flowing} {Polymer} {Solutions}},
volume = {32},
journal = {Preprints of the ACS-meeting,Atlanta,USA, April 1991},
author = {Horst, Roland and Wolf, Bernhard Anton},
year = {1991},
pages = {511},
}
@patent{weinmann_verfahren_1993,
address = {Deutschland},
title = {Verfahren und {Vorrichtung} zur technischen {Fraktionierung} von {Polymeren}},
abstract = {PATENT: (C2) Bei einem Verfahren zur technischen Fraktionierung von Polymeren unter Verwendung einer Extraktionskolonne und eines homogenen Extraktionsagens wird ein homogener Feed einem Bereich der Extraktionskolonne zugefuehrt, der von deren oberen Ende naeher beabstandet ist, wenn der Feed eine groessere Dichte als das Extraktionsagens aufweist, und der von deren unteren Ende naeher beabstandet ist, wenn der Feed eine geringere Dichte als das Extraktionsagens aufweist. Eine Vorrichtung zur Durchfuehrung dieses Verfahrens besteht vorteilhaft statt bisher aus einer gepulsten Siebbodenkolonne aus einer ungepulsten Fuellkoerperkolonne, die zu einer besseren Auftrennung fuehrt, da eine Rueckvermischung in guenstiger Weise vermieden wird.},
nationality = {C08F006-04},
language = {German},
assignee = {Pluess-Staufer AG},
number = {DE4104573.4},
author = {Weinmann, Klaus and Tschersich, Lutz and Wolf, Bernhard Anton},
month = jan,
year = {1993},
pages = {Textseiten 25; Blattzahl 16; Zeichnungsseiten 5; Filmlochkarten 4},
}
@article{schneider_thermoreversible_1991,
title = {Thermoreversible {Gelation} and {Vitrification} of {Highly} {Concentrated} {Polymer}-{Solutions} under {Poor} {Thermodynamic} {Conditions}},
volume = {24},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1991&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00019a028},
abstract = {Differential scanning calorimetry (DSC) and dielectric relaxation spectroscopy (DRS) demonstrate that highly concentrated solutions of poly(n-butyl methacrylate) (PBMA; M(w) = 450 000, M(w)/M(n) = 1.06) in 2-propanol (2-POH) solidify upon cooling in two clearly distinguishable steps. With this endothermal system, for which the THETA-temperature (24-degrees-C) is almost identical with the glass transition temperature of the pure polymer (22-degrees-C), the solutions gel thermoreversibly some 60-40-degrees-C before they become glassy. The gelation is interpreted in terms of noncrystalline physical cross-links, which result from the preference of the energetically highly favored polymer/polymer contacts over polymer/solvent contacts; the resulting intersegmental clusters amplify a partial freezing-in of the mobility of the macromolecules that can already be observed in the absence of solvent by means of DRS measurements. Qualitatively the glass transition temperature of the pure PBMA is changed by the addition of 2-POH in the usual way. The low solvent quality, however, causes extra effects, which favor the vitrification. A so far only empirical equation is proposed to describe these thermodynamic contributions.},
language = {English},
number = {19},
journal = {Macromolecules},
author = {Schneider, T. and Wolf, B. A. and Kasten, H. and Kremer, F.},
month = sep,
year = {1991},
keywords = {atactic polystyrene solutions, cooccurrence},
pages = {5387--5392},
}
@article{wolf_thermoreversible_1991,
title = {Thermoreversible {Gelation} and {Vitrification} of {Concentrated} {Polymer}-{Solutions} under {Poor} {Thermodynamic} {Conditions}},
volume = {202},
issn = {0065-7727},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1991&action=retrieve&mode=FullRecord},
language = {English},
journal = {Abstracts of Papers of the American Chemical Society},
author = {Wolf, B. A. and Schneider, T.},
month = aug,
year = {1991},
pages = {146--POLY},
}
@article{weinmann_theory-based_1992,
title = {Theory-{Based} {Improvements} of {Continuous} {Polymer} {Fractionation} {Demonstrated} for {Poly}({Carbonate})},
volume = {45},
issn = {0021-8995},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1992&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/app.1992.070450715},
abstract = {For the first time, a quantitative theoretical analysis (liquid / liquid phase equilibria treated by means of the continuous thermodynamics) of the operating characteristics of continuous polymer fractionation (CPF) was performed. The results of these calculations were compared with data published for CPF of polyethylene. It turned out that the efficiency of the conventional CPF corresponds to approximately two theoretical plates only. For this reason, several improvements, suggested by theoretical considerations, were realized experimentally, for which purpose the system dichloromethane/diethylene glycol/bisphenol-A polycarbonate was chosen. The pulsating sieve-bottom column was replaced by a nonpulsating column filled with glass beads. In this manner, the number of theoretical plates could be raised considerably. A further improvement of the fractionation efficiency results from the reflux of part of the polymer contained in the sol phase. In praxi, this situation was realized by putting a condensor on top of the column and introducing the feed somewhere near its upper third. After predictive calculations and orienting experiments, 125 g of a polycarbonate with M(w) = 29 kg/mol and a nonuniformity U = 1.3 were fractionated in four consecutive CPF runs (where the gels were directly used as feed for the next step) into five fractions of approximately equal weight. Except for the lowest-molecular-weight fraction, one obtains nonuniformities on the order of 0.1.},
language = {English},
number = {7},
journal = {Journal of Applied Polymer Science},
author = {Weinmann, K. and Wolf, B. A. and Ratzsch, M. T. and Tschersich, L.},
month = jul,
year = {1992},
keywords = {pib},
pages = {1265--1279},
}
@article{ballauff_degradation_1984,
title = {Degradation of {Chain} {Molecules} .2. {Thermodynamically} {Induced} {Shear} {Degradation} of {Dissolved} {Polystyrene}},
volume = {17},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1984&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00132a016},
language = {English},
number = {2},
journal = {Macromolecules},
author = {Ballauff, M. and Wolf, B. A.},
year = {1984},
pages = {209--216},
}
@article{heinrich_interfacial-tension_1992,
title = {Interfacial-{Tension} between {Solutions} of {Polystyrenes} - {Establishment} of a {Useful} {Master} {Curve}},
volume = {33},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1992&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/0032-3861(92)90494-H},
abstract = {The interfacial tension-sigma between the coexisting phases of the systems methylcyclohexane/polystyrene and cyclohexane/polystyrene was measured by means of the spinning drop and sessile drop methods as a function of (T(c) - T)/T(c) = tau, the reduced distance from the critical temperature, for different relative molar masses M of the polymer (17 500 - 175 000). The minimum tau-value that could be realized amounted to 1.7 x 10(-3) and the corresponding sigma-value to 0.0007 mN m-1. The results were evaluated according to the relations (1) ln-sigma = A - zeta(mu)ln M + mu-ln-tau and (2) ln-DELTA-phi = B - zeta(beta) ln M + beta-ln-tau in which DELTA-phi is the difference in the volume fraction of the polymer in the coexisting phases, A and B are constants for a given solvent, and zeta(mu), zeta(beta), mu and beta are the critical exponents. With increasing M the exponent-mu is found to fall from values which are close to that predicted by the mean-field theory (1.50) to those resulting from the Ising model (1.26); beta equals 0.35 in the entire region of M (mean-field: 0.50, Ising: 0.31). In contrast to the critical exponents, A and B are not universal constants but vary from solvent to solvent, i.e. the above relations are of little use for the prediction of sigma. This deficiency can, however, be overcome by substituting tau from (2) into (1) and replacing M by N, the number of monomeric units. The different parameters of the resulting relation (3) ln-sigma = D + delta-ln N + (mu/beta) ln-DELTA-phi no longer depend on the particular chemical nature of the system. It therefore constitutes a useful master curve to obtain sigma from knowledge of the composition of the coexisting phases. The evaluation of the present measurements together with unpublished material yields D = ln[0.153 (mN m-1)], delta = (zeta(beta)mu/beta) - zeta(mu) = 0.50 (identical with the mean-field value) and mu/beta = 3.85 (mean-field: 3.00, Ising: 4.00).},
language = {English},
number = {9},
journal = {Polymer},
author = {Heinrich, M. and Wolf, B. A.},
year = {1992},
keywords = {polystyrene, system, coexistence curve, critical solution temperatures, cyclohexane, interfacial tension, master curve, phase-separation, polymer-solutions},
pages = {1926--1931},
}
@article{geerissen_pressure-dependence_1991,
title = {{PRESSURE}-{DEPENDENCE} {OF} {VISCOMETRIC} {RELAXATION}-{TIMES} {MEASURED} {WITH} {A} {NEW} {APPARATUS} - {WILLIAMS}-{LANDEL}-{FERRY} {BEHAVIOR} {OF} {MODERATELY} {CONCENTRATED}-{SOLUTIONS} {OF} {POLY}({BUTYL} {METHACRYLATE}){S} {IN} 2-{PROPANOL}},
volume = {192},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1991&action=retrieve&mode=FullRecord},
abstract = {A new rotational viscometer is presented which can be operated up to 2 000 bar and a maximum shear stress of 420 Pa. It allows, for the first time, to investigate the non-Newtonian flow behaviour of moderately concentrated polymer solutions. Results of measurements with two representatives of the system 2-propanol/poly(butyl methacrylate) with weight-average molecular weights MBAR(w) = 520 000 and MBAR(w) = 2 050 000, and ratios of weight- to number-average molecular weights MBAR(w)/MBAR(n) = 1,08 and MBAR(w)/MBAR(w) = 1,23, resp.) in the region of moderate polymer concentrations are reported. For a ca. 7 wt.-\% solution of the higher-molecular-weight polymer one obtains viscometric relaxation times tau-0 varying from 1 to 100 ms in the region from 1 to 2 000 bar and from 40 to 75-degrees-C; at the lower temperature the application of p can raise tau-0 by one order of magnitude. The steady-state shear compliance (proportional to tau-0/eta-0, where eta-0 is the zero-shear viscosity), is independent of pressure or varies only slightly. For the present system, which gels thermoreversibly upon cooling, eta-0 and tau-0 as a function of temperature and pressure can be well represented by the Williams-Landel-Ferry equation.},
language = {English},
number = {1},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Geerissen, H. and Gernandt, F. and Wolf, B. A. and Lentz, H.},
month = jan,
year = {1991},
keywords = {polymer-solutions},
pages = {165--176},
}
@article{muniz_polymer-polymer_1992,
title = {Polymer-{Polymer} {Miscibility} {Evaluation} by {Acoustic}-{Emission}},
volume = {13},
issn = {0173-2803},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1992&action=retrieve&mode=FullRecord},
language = {English},
number = {1},
journal = {Makromolekulare Chemie-Rapid Communications},
author = {Muniz, E. C. and Vasquez, P. A. M. and Bruns, R. E. and Nunes, S. P. and Wolf, B. A.},
month = jan,
year = {1992},
keywords = {behavior, polyvinyl-chloride) blends},
pages = {45--53},
}
@article{heinrich_interfacial-tension_1992-1,
title = {Interfacial-{Tension} between {Demixed} {Solutions} of {Molecularly} {Nonuniform} {Polymers}},
volume = {25},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1992&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00040a033},
language = {English},
number = {14},
journal = {Macromolecules},
author = {Heinrich, M. and Wolf, B. A.},
month = jul,
year = {1992},
keywords = {continuous fractionation, pib},
pages = {3817--3819},
}
@article{ratzsch_application_1991,
title = {{APPLICATION} {OF} {CONTINUOUS} {THERMODYNAMICS} {TO} {POLYMER} {FRACTIONATION}},
volume = {63},
issn = {0033-4545},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1991&action=retrieve&mode=FullRecord},
doi = {10.1351/pac199163101511},
abstract = {Continuous thermodynamics has been recently developed and applied to the liquid-liquid equilibrium of polydispersed polymer solutions. It uses the continuous distribution function directly in the thermodynamic equations to achieve a concise and convenient treatment of polydispersed systems. This paper presents the application of continuous thermodynamics to successive polymer fractionation procedures based on solubility differences. The method is then applied to describe Baker-Williams column fractionation. Lastly, it is used to model continuous polymer fractionation that splits the polymer into two fractions that can be fractionated again.},
language = {English},
number = {10},
journal = {Pure and Applied Chemistry},
author = {Ratzsch, M. T. and Kehlen, H. and Tschersich, L. and Wolf, B. A.},
month = oct,
year = {1991},
pages = {1511--1518},
}
@article{horst_calculation_1992,
title = {Calculation of the {Phase}-{Separation} {Behavior} of {Sheared} {Polymer} {Blends}},
volume = {25},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1992&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00046a029},
abstract = {The influence of shear on the phase diagrams of model blends of polymer A and polymer B, exhibiting phase separation upon heating, was calculated on the basis of the generalized Gibbs energy of mixing G(gamma), characterizing the steady state established at shear rate gamma, as the sum of G(z), the equilibrium Gibbs energy, and E(s), the energy the system can store while flowing. The results obtained for the two model systems A150/B200 and A75/B200 (the figures denote the molar masses in kg/mol) are qualitatively identical. With increasing shear rate the homogeneous region expands first, then shrinks below its equilibrium value within a certain gamma range, and finally becomes again larger than with the stagnant blends. For a given composition of such a polymer mixture two regions of shear dissolution at low and at high gamma values, respectively, are separated by a region of shear demixing; hence two inversion points of shear influences are theoretically expected for blends, in contrast to polymer solutions, for which one calculates only one. Experimentally, the inversion from shear dissolution to shear demixing is frequently observed and the opposite inversion was recently reported for the first time, but so far no evidence exists for the occurrence of both phenomena within the same system. Possible reasons for this fact are discussed.},
language = {English},
number = {20},
journal = {Macromolecules},
author = {Horst, R. and Wolf, B. A.},
month = sep,
year = {1992},
keywords = {flow, polystyrene, apparatus, miscibility},
pages = {5291--5296},
}
@article{wolf_cpf_1992,
title = {{CPF} - {CONTINUOUS} {POLYMER} {FRACTIONATION}},
volume = {61},
issn = {0258-0322},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1992&action=retrieve&mode=FullRecord},
doi = {10.1002/masy.19920610119},
abstract = {A method is presented by means of which it is possible to fractionate polymers according to their solubility on a technical scale. The CPF consists of a continuous counter-current extraction process in which a homogeneous mixture of a molecularly or/and chemically non-uniform high molecular weight product is divided into two portions of considerably lower non-uniformity. The principle of the CPF is described in general terms and examples are given for the fractionation of homopolymers.},
language = {English},
journal = {Makromolekulare Chemie-Macromolecular Symposia},
author = {Wolf, B. A.},
month = aug,
year = {1992},
pages = {244--247},
}
@article{wagner_effect_1993,
title = {Effect of {Block} {Copolymers} on the {Interfacial}-{Tension} between 2 {Immiscible}/{Homopolymers}},
volume = {34},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1993&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/0032-3861(93)90862-5},
abstract = {The effect of block copolymers on the interfacial tension sigma was investigated for poly(ethylene oxide) (PEO)/poly(dimethylsiloxane) (PDMS) and for PDMS/polystyrene (PS). With PEO/PDMS the additives were the triblock copolymers PDMS-block-PEO-block-PDMS [P(DMS-EO-DMS)] and PEO-block-PDMS-block-PEO [P(EO-DMS-EO)]. For the former additive the number of monomeric units of the end blocks varied between 4 and 32 and that of the middle block between 23 and 77; these numbers are 70 and 52, respectively, for the latter. In the case of the system PS/PDMS, the diblock copolymer PS-block-PDMS [P(S-DMS)], consisting of 430 S and 68 DMS units, was studied. The effects turned out to be largest for the system PDMS/PEO/P(DMS-EO-DMS); it was therefore studied in greater detail within the temperature range of 70-150-degrees-C. Upon addition of increasing amounts of copolymer, sigma falls rapidly to approximately 10\% of its initial value and levels off as the critical micelle concentration ({\textless} 0.5 wt\% in the PEO phase at 100-degrees-C) is surpassed. Similarly, at a given concentration of the additive, sigma approaches a limiting value as the number of monomeric units in the PDMS block is increased above 15. In contrast to the value of sigma of the pure blend, which is practically independent of temperature, that of the ternary system increases markedly with temperature. The results are compared with the predictions of Vilgis and Noolandi.},
language = {English},
number = {7},
journal = {Polymer},
author = {Wagner, M. and Wolf, B. A.},
year = {1993},
keywords = {polystyrene, interfacial tension, block copolymers, co-polymers, diblock copolymers, homopolymer blends, phase-separation kinetics, polymer blend, polysiloxane},
pages = {1460--1464},
}
@article{horst_pressure_1993,
title = {{PRESSURE} {AND} {SOLVENT} {INFLUENCES} {ON} {THE} {SHEAR} {THINNING} {BEHAVIOR} {OF} {MODERATELY} {CONCENTRATED}-{SOLUTIONS} {OF} {POLY}({BUTYL} {METHACRYLATE})},
volume = {194},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1993&action=retrieve&mode=FullRecord},
abstract = {The viscosities of moderately concentrated solutions of poly(butyl methacrylate) - M(w)BAR = 1820 kg/mol - in the thermodynamically good solvent toluene and in the theta solvent 2-propanol were measured up to pressures of 2000 bar as a function of shear rate gamma in the temperature interval from 40 to 70-degrees-C. Both systems obey Graessley's equation so that it is possible to obtain the following rheological parameters in addition to the zero-shear viscosity eta0 from the dependences eta(gamma). Eta can be split into an entanglement part eta(ent) plus a frictional contribution eta(fric), and the characteristic viscometric relaxation time tau0 becomes accessible. The present results demonstrate that the application of pressure raises the above parameters much less for good than for bad solvents. In contrast to eta(fric) (which can react differently to the application of pressure due to special circumstances) eta0 and tau0 are always influenced to the same degree as T or p are changed. This result implies that the steady state shear compliance (tau0/eta0) is independent of the variables of state irrespective of the thermodynamic quality of the solvent. For the good solvent the effects of temperature can be described by the Arrhenius equation, whereas the WLF equation has to be used for the bad one.},
language = {English},
number = {5},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Horst, R. and Mertsch, R. and Wolf, B. A.},
month = may,
year = {1993},
pages = {1387--1395},
}
@article{wolf_intramolecular_1993,
title = {Intramolecular {Interaction} of {Chain} {Molecules} - 2nd {Osmotic} {Virial}-{Coefficients} and {Intrinsic} {Viscosities}},
volume = {194},
issn = {0025-116X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1993&action=retrieve&mode=FullRecord},
abstract = {In a new theoretical approach the separation of a pair of chain molecules (measured thermodynamically by the second osmotic virial coefficient A2) is treated as a two-step process: In the first step the molecules are detached from each other by the addition of solvent - keeping their dimensions constant - and in the second step the now isolated coils are allowed to relax into their equilibrium dimensions. For the description of the second step, in which only segments belonging to one molecule take part, an intra-molecular interaction parameter is introduced on the basis of the intrinsic viscosity. The present two-parameter approach yields A2 = A2infinity + sigma M-(1-a) for the dependence of A2 on the molecular weight M of the polymer; a is the exponent of the Kuhn-Mark-Houwink equation and sigma a parameter measuring the effects associated with the second step (becoming zero if the coil dimensions do not depend on polymer concentration). A test of the above relation by means of published material demonstrates its superiority over other two-parameter theories: It can describe the actually measured A2(M) well down into the region of oligomers without an additional parameter and it comprises the conceptual advantage of explaining experimental observations concerning partial derivative A2/partial derivative M {\textgreater} 0 or partial derivative A2/partial derivative M almost-equal-to 0 for high A2 values.},
language = {English},
number = {5},
journal = {Makromolekulare Chemie-Macromolecular Chemistry and Physics},
author = {Wolf, B. A.},
month = may,
year = {1993},
keywords = {polymer, weight dependence},
pages = {1491--1504},
}
@incollection{wolf_continuous_1994,
address = {Oxford, New York, Seoul, Tokyo},
title = {Continuous {Polymer} {Fractionation}},
booktitle = {Encyclopedia of advanced materials},
publisher = {Pergamon Press},
author = {Wolf, Bernhard Anton},
editor = {Bloor, D. and Brook, R. J. and Flemings, M. C. and Mahajan, S.},
year = {1994},
pages = {881--885},
}
@inproceedings{hoecker_cpf_1993,
address = {London},
title = {{CPF}: {A} new {Method} for {Large}-{Scale} {Fractionation} of {Polymers}},
volume = {2},
publisher = {Elsevier Applied Science},
author = {Hoecker, Bernd and Petri, Hans-Michael and Weinmann, Klaus and Wolf, Bernhard Anton},
editor = {Logsdail, D. H. and Slater, M. J.},
year = {1993},
pages = {1109--1115},
}
@incollection{wolf_flow-induced_1995,
address = {Lancaster Pa, USA and Basel CH},
title = {Flow-induced {Dissolution}/{Demixing} in {Polymeric} {Systems} - {A} {Predictive} {Scheme}},
booktitle = {Application of {Rheo}-optical {Techniques} for {Analyzing} {Multiphase} {Polymer} {Systems}},
publisher = {Technomic Publishing Company},
author = {Wolf, Bernhard Anton and Horst, Roland},
editor = {Søndergaard, K. and Lyngaae-Jørgensen, J.},
year = {1995},
pages = {323--355},
}
@article{horst_refined_1993,
title = {Refined {Calculation} of the {Phase}-{Separation} {Behavior} of {Sheared} {Polymer} {Blends} - {Closed} {Miscibility} {Gaps} within 2 {Ranges} of {Shear} {Rates}},
volume = {26},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1993&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00073a022},
abstract = {The phase diagrams of a blend of two homopolymers exhibiting a lower critical solution temperature (LCST) have been calculated on the basis of the generalized Gibbs energy of mixing (sum of the Gibbs energy of mixing of the stagnant blend and the energy the mixture can store during stationary flow) for various shear rates gamma. In the present paper the temperature dependence of the energy stored in blends was taken into account. The calculations yield a complex dependence: With increasing gamma the heterogeneous region of the phase diagram is first reduced (shear dissolution), then enlarged (shear demixing), and finally reduced again. So, with varying gamma, the influences of shear change sign twice; i.e., two inversions of the effects are observed. For very high gamma values the system behaves like in the quiescent state. Closed miscibility gaps can occur within two ranges of gamma: Within the first range the islands show up below T(c) (the critical temperature of the system) and merge into the original miscibility gap as gamma is raised; the first inversion point is located in this area. The second gamma range of islands (entirely located above T(c)) is observed within the regime of the second shear dissolution. The occurrence of islands can be suppressed for an appropriate choice of parameters and the previously published simpler behavior is regained.},
language = {English},
number = {21},
journal = {Macromolecules},
author = {Horst, R. and Wolf, B. A.},
month = oct,
year = {1993},
keywords = {flow, polystyrene, apparatus, angle neutron-scattering, fluorescence, temperature, viscosity},
pages = {5676--5680},
}
@article{fernandez_complex_1995,
title = {Complex {Miscibility} {Behavior} for {Polymer} {Blends} in {Flow}},
volume = {36},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1995&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/0032-3861(95)90686-V},
abstract = {Experimental observations of the effect of shear flow on the miscibility of binary polymer blends an compared to calculations based on a generalized Gibbs energy of mixing G gamma. This mixing free energy characterizes the steady state established at shear rate gamma, as the sum of G(Z), the equilibrium Gibbs energy and E(S), the energy the system stores while flowing.},
language = {English},
number = {1},
journal = {Polymer},
author = {Fernandez, M. L. and Higgins, J. S. and Horst, R. and Wolf, B. A.},
month = jan,
year = {1995},
keywords = {polystyrene, polyvinyl methyl-ether), miscibility, homogeneous melt state, insitu fluorescence, kinetics, phase-separation behavior, polymer blends, scattering, shear, shear-flow, solution-chlorinated polyethylene, transitions},
pages = {149--154},
}
@article{heinrich_establishment_1993,
title = {Establishment of {Phase}-{Equilibria} - {Temperature}-{Jump} {Experiments} in a {Spinning}-{Drop} {Apparatus}},
volume = {26},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1993&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00074a036},
abstract = {In a spinning-drop apparatus, used for the determination of interfacial tensions, it was investigated how phase-separated polymer solutions react on a rapid rise in temperature. These measurements, yielding an apparent interfacial tension as a function of time, demonstrate that new equilibria are achieved in four clearly separable steps. The first, very rapid one consists in the establishment of a local equilibrium within the interfacial area dividing the two coexisting liquids. During the second stage of much longer duration, solvent and solute are exchanged between the bulk material as a result of the gradients in the chemical potential that exist for both components in both phases; due to the higher mobility of the solvent, its flux dominates. This stage comes to an end as one of the coexisting phases assumes its equilibrium composition, i.e., falls on one end of the corresponding tie line. Despite this situation the entire system has not yet reached equilibrium since the composition of the other coexisting phase is not identical with that of the other end of the tie line. The third step, which is again long-lasting, is therefore characterized by the transport of only one component over the phase boundary, namely for one for which still exists a driving force. If the droplet consists of the dilute polymer solution and the matrix of the concentrated polymer solution, it is the solvent which migrates exclusively during that stage; in the opposite case it is the polymer. If the overall composition of the system corresponds to a point within the homogeneous region of the phase diagram, this third step is followed by a fourth. Ultimately, the new equilibrium is achieved by mere diffusion in the absence of a discontinuity in concentration. Since the spinning-drop experiments also allow the determination of the volume of the phases and the interfacial area between them, it is possible to determine the net fluxes for the first three stages; some preliminary data are given. Furthermore, it is possible to visualize the volume elements within which the composition has changed during equilibrium by jumping back to the lower starting temperature by means of the phase separation that takes place in these zones.},
language = {English},
number = {22},
journal = {Macromolecules},
author = {Heinrich, M. and Wolf, B. A.},
month = oct,
year = {1993},
keywords = {curve, interfacial-tension},
pages = {6106--6110},
}
@article{petri_concentration-dependent_1994,
title = {Concentration-{Dependent} {Thermodynamic} {Interaction} {Parameters} for {Polymer}-{Solutions} - {Quick} and {Reliable} {Determination} {Via} {Normal} {Gas}-{Chromatography}},
volume = {27},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1994&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00088a010},
abstract = {Equilibrium vapor pressures were determined by combining a head-space sampler with a gas chromatograph for the system cyclohexane/polystyrene in the temperature range from 35 to 65-degrees-C. From these measurements the Flory-Huggins interaction parameter chi, its variation with phi2, the volume fraction of the polymer, and its enthalpy part were calculated; chi(phi2) was represented by an analytical expression given by Koningsveld and Kleintjens and compared with different experimental findings reported in the literature. All measurements agree reasonably well at 35-degrees-C (in the vicinity of the THETA temperature of the system). Differences develop as T is raised; at 65-degrees-C chi and its concentration dependence are found to be less pronounced than reported. Under these conditions there also exists a discrepancy between the values calculated from chi(phi2) for vanishing polymer concentration and those directly measured. The reasons for that observation are discussed. The present work demonstrates that the new method yields quick and reliable information on chi(phi2;T).},
language = {English},
number = {10},
journal = {Macromolecules},
author = {Petri, H. M. and Wolf, B. A.},
month = may,
year = {1994},
keywords = {polystyrene, systems},
pages = {2714--2718},
}
@article{wagner_interfacial-tension_1993,
title = {Interfacial-{Tension} between {Poly}({Isobutylene}) and {Poly}({Dimethylsiloxane}) - {Influence} of {Chain}-{Length}, {Temperature}, and {Solvents}},
volume = {26},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1993&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00076a029},
abstract = {The interfacial tension sigma was determined by means of spinning-drop and sessile-drop measurements for binary mixtures of low molecular weight and comparatively uniform fractions of poly(isobutylene) (PEB: 1.5, 3.3, and 5.0 kg/mol) plus poly(dimethylsiloxane) (PDMS: 11.3 and 19.6 kg/mol) as a function of temperature (20-80-degrees-C). All values lie in the range between 2.5 and 4.0 mN/m. For PIB-1.5/PDMS-11.3 sigma increases with T, for PIB-3.3/PDMS-11.3 it passes a maximum, and for PIB-5.0/PDMS-11.3 it decreases; these observations are interpreted in terms of closed miscibility gaps. At 25-degrees-C it was also investigated how the addition of solvents of different thermodynamic quality changes the interfacial tension between PIB and PDMS. With toluene, a good solvent for both polymers, sigma reduces monotonously to zero. With methyl ethyl ketone, which is a marginal solvent for PIB and a good solvent for PDMS, sigma passes a distinct minimum; this finding indicates cosolvency. None of the different existing theories can predict the experimental observations satisfactorily.},
language = {English},
number = {24},
journal = {Macromolecules},
author = {Wagner, M. and Wolf, B. A.},
month = nov,
year = {1993},
keywords = {immiscible polymer blends},
pages = {6498--6502},
}
@article{muniz_shear_1994,
title = {{SHEAR} {INFLUENCE} {ON} {THE} {PHASE}-{SEPARATION} {OF} {OLIGOMER} {BLENDS}},
volume = {195},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1994&action=retrieve&mode=FullRecord},
doi = {10.1002/macp.1994.021950412},
abstract = {Shear influences on the phase separation behaviour of four different blends of ethylene glycol/propylene glycol oligomers, exhibiting upper critical solution temperatures, were investigated. Cloud point curves at rest (turbidity measurements) are reported for all systems, spinodal conditions (light scattering) and tie-lines (analysis of the coexisting phases) are given for some examples. Phase diagrams under shear were obtained from rheological data. They demonstrate that the demixing temperatures of systems where both glycols bear OH end-groups are lowered up to ca. 1-degrees-C by shear rates of 1000 s-1; the critical composition, generalized to the non-equilibrium conditions of flow, is markedly shifted. These observations are explained in terms of the generalized Gibbs energy (containing the mechanical energy the system stores during flow) as a consequence of the strongly interacting end-groups of the glycols. This interpretation is backed by the fact that the shear effects disappear when the glycols are methylated.},
language = {English},
number = {4},
journal = {Macromolecular Chemistry and Physics},
author = {Muniz, E. C. and Nunes, S. P. and Wolf, B. A.},
month = apr,
year = {1994},
keywords = {flow, polymer-solutions, behavior, viscosity, ethylene-oxide, propylene-oxide oligomers},
pages = {1257--1271},
}
@article{geerissen_capillary_1993,
title = {{CAPILLARY} {VISCOMETER} {OPERATING} {AT} {HIGH}-{TEMPERATURES}},
volume = {35},
issn = {0507-5475},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1993&action=retrieve&mode=FullRecord},
abstract = {A modification of the design of an industrial Ubbelohde viscometer, to make it possible to operate in the automated mode is described. The new design considerably simplifies the procedure of polymer characterization.},
language = {Russian},
number = {5},
journal = {Vysokomolekulyarnye Soedineniya Seriya a \& Seriya B},
author = {Geerissen, H. and Schutzeichel, P. and Wolf, B.},
month = may,
year = {1993},
pages = {A579--A581},
}
@article{siqueira_solution_1994,
title = {Solution {Properties} of a {Diblock} {Copolymer} in a {Selective} {Solvent} of {Marginal} {Quality} .1. {Phase}-{Diagram} and {Rheological} {Behavior}},
volume = {27},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1994&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00079a035},
abstract = {A diblock copolymer of styrene and butyl methacrylate with narrow molecular weight distribution [P(S-b-BMA)] containing 1200 monomeric units of S and 1250 of BMA was studied in 2-propanol [2-POH], which is a nonsolvent for the S blocks and a theta solvent (UCST) for the BMA blocks. The phase diagram of the present system is almost indistinguishable from that of 2-POH/PBMA if the molecular weight of the homopolymer is identical with that of the BMA block. The comparison of the intrinsic viscosities [eta] of P(S-b-BMA) and PBMA in 2-POH and of their variation with temperature demonstrates that eta reflects the presence of micelles rather than unimers. The theological behavior of moderately concentrated solutions can be understood in terms of an overlap concentration c() defined as eta(-1). Below c() the viscosity eta changes with temperature as usual, and the liquids are:Newtonian up to rates gamma of several thousand inverse seconds. Above c(*) the viscosity increases up to 1 order of magnitude as T is raised; shear thinning is observed within the entire gamma range under investigation. All experimental findings can be consistently explained in terms of micelles in which the S blocks are effectively hidden in the cores and the PBMA blocks form the outer shell. The inverse temperature dependence of eta stems from the expansion of the PBMA layers resulting from the improvement of thermodynamic quality of the solvent with rising distance from the miscibility gap of the system; the higher the temperature becomes, the more the coronae of the micelles penetrate each other and the more their relative movement is hindered.},
language = {English},
number = {1},
journal = {Macromolecules},
author = {Siqueira, D. F. and Nunes, S. P. and Wolf, B. A.},
month = jan,
year = {1994},
keywords = {cooccurrence, polymer-solutions, viscosity, shear, block copolymer, thermoreversible gelation},
pages = {234--239},
}
@article{horst_calculation_1994,
title = {{CALCULATION} {OF} {SHEAR} {INFLUENCES} {ON} {THE} {PHASE}-{SEPARATION} {OF} {POLYMER} {BLENDS} {EXHIBITING} {UPPER} {CRITICAL} {SOLUTION} {TEMPERATURES}},
volume = {33},
issn = {0035-4511},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1994&action=retrieve&mode=FullRecord},
doi = {10.1007/bf00366754},
abstract = {Calculations were performed on the basis of a generalized Gibbs energy of mixing G(gamma), which is the sum of the Gibbs energy of mixing of the stagnant system and E(s), the energy stored in the system during stationary flow. With increasing shear rate gamma, the demixing temperatures shift to lower values (shear-induced mixing; diminution of the heterogeneous area), then to higher values (shear-induced demixing), and finally to lower values again before the effects fade out. The details of the rather complex phase diagrams resulting for a given shear rate are primarily determined by a band in the T/x plane (x = mole fraction) within which (partial derivative 2 E(s)/partial derivative x2)T {\textless} 0 (i.e., E(s) acts towards phase separation). There are two ranges of gamma within which closed miscibility gaps can exist: The more common outer islands are partly or totally situated outside the equilibrium gap (and within the above mentioned band). As gamma is raised they break away from the ''mainland'' at the upper end of the first region of shear-induced mixing and shift to T {\textgreater} UCST where they submerge. Bound to a suitable choice of parameters, a second kind of closed miscibility gaps, the inner islands, which always remain within the equilibrium solubility gap (and outside the band of negative curvature of E(s)) is additionally observed. This time the islands break away from the ''mainland'' at the lower end of the first region of shear-induced mixing where they also submerge. The present findings are compared with the results of previous calculations for LCSTs.},
language = {English},
number = {2},
journal = {Rheologica Acta},
author = {Horst, R. and Wolf, B. A.},
month = apr,
year = {1994},
keywords = {flow, polystyrene, behavior, apparatus, polymer blend, angle neutron-scattering, insitu fluorescence, transitions, closed, closed miscibility gaps, homogeneous melt, methyl-ether), miscibility gap, phase separation, shear flow, state, stored energy, ucst},
pages = {99--107},
}
@article{siqueira_solution_1994-1,
title = {Solution {Properties} of a {Diblock} {Copolymer} in a {Selective} {Solvent} of {Marginal} {Quality} .2. {Characterization} of {Micelles} and {Surface}-{Tension}},
volume = {27},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1994&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00094a020},
abstract = {Solutions of polystyrene-block-poly(butyl methacrylate) [P(S-b-BMA]-a narrowly distributed linear diblock copolymer consisting of 1200 monomeric units of styrene and 1200 units of butyl methacrylate-in 2-propanol (a nonsolvent for the S blocks and a THETA solvent (THETA = 23-degrees-C) for the BMA blocks) were studied by carring out the following measurements: dynamic (DLS) and static light scattering (SLS), transmission elctron microscopy (TEM), small-angle X-ray scattering (SAXS), and surface tension. The results demonstrate that the polymer forms micelles as soon as a very low critical micelle concentration ({\textless}4 X 10(-3) wt \%) is exceeded. According to SLS these entities consist of approximately 75 unimers and exhibit an apparent radius of gyration of ca. 37 nm; this value is (in agreement with theoretical considerations) somewhat less than the sum of the radii of the S cores and of the BMA coronas, which are according to TEM 25 nm each. The hydrodynamic radius of the micelles observed in the DLS is 56 nm. It is concluded from SAXS (up to 15 wt \%) of P(S-b-BMA) and from TEM that the core of the micelles does not change in size or shape; this finding is at variance with an increase of the aggregation number upon dilution concluded from SLS. The presence of micelles lowers the surface tension of the solvent measurably; the maximum reduction of ca. 1.5 mN/m is reached at a polymer concentration of 0.01 wt \%, when the aggregates cover the entire surface.},
language = {English},
number = {16},
journal = {Macromolecules},
author = {Siqueira, D. F. and Nunes, S. P. and Wolf, B. A.},
month = aug,
year = {1994},
keywords = {polymer-solutions, block-copolymer, electron-microscopy},
pages = {4561--4565},
}
@article{mertsch_significance_1994,
title = {On the {Significance} of {Molecular}-{Surfaces} and {Thermodynamic} {Interactions} for the {Excess} {Viscosities} of {Liquid}-{Mixtures}},
volume = {98},
issn = {0005-9021},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1994&action=retrieve&mode=FullRecord},
abstract = {The viscosities eta of homogeneous binary mixtures of liquids are usually approximated as ln eta = phi(1) ln eta(1) +phi(2) ln eta(2) where phi i and eta i are the volume fractions and the viscosities, reap., of the i-th pure substance; the behavior of real systems is then discussed in terms of Delta ln eta, the deviations from the above reference behavior. Here a semi-empirical approach is presented according to which volume fractions are replaced by the surface fractions Omega(i) to create a more realistic reference state, and the thermodynamic interaction parameter g is taken into account. The new equation reads (expressing it for practical purposes still in the terms of phi(1)) Delta ln eta = gamma delta/1+gamma phi(2) phi(2)(1-phi(2))+2g (1+gamma)/(1+gamma phi(2))(2) phi(2) (1-phi(2)); gamma is a geometric factor, measuring the difference between Omega(i) and phi(i), and delta = ln (eta(2)/eta(1)). The comparison of calculations according to the above equation with experimental data demonstrates that the first term is decisive in the majority of cases and only with systems of large interaction does the second become important. For all nine systems under investigation quantitative agreement between experiment and theory can be achieved using a theoretical value for either gamma or g, and adjusting the other within physically reasonable limits. Possible explanations for the necessity to fit one of the parameters are given.},
language = {English},
number = {10},
journal = {Berichte Der Bunsen-Gesellschaft-Physical Chemistry Chemical Physics},
author = {Mertsch, R. and Wolf, B. A.},
month = oct,
year = {1994},
keywords = {viscosity, binary liquid mixtures, thermodynamics},
pages = {1275--1280},
}
@article{mertsch_viscosity_1994,
title = {Viscosity and {Mixing} {Behavior} of the {System} {Ethylene} {Polyisobutylene}},
volume = {7},
issn = {0896-8446},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1994&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/0896-8446(94)90021-3},
abstract = {Two samples of polyisobutylene (PlB 3.9 with (\\() over bar M(w) = 3.9 kg mol(-1) and (\\)) over bar M(w)/(\\() over bar M(n) = 1.30; and PIB 1.4 with (\\)) over bar M(w) = 1.40 kg mol(-1) and (\\() over bar M(w)/(\\)) over bar M(n) = 1.56) were obtained by means of continuous polymer fractionation. The minimum pressures required to achieve complete miscibility of these polymers with ethylene (Et) in the temperature range from 30 to 70 degrees C are on the order of 200 to 500 bar. The zero shear viscosities of th mixtures are in all cases found to be less than the values calculated from the additivity of eta(0) of the components in terms of volume fractions. The transition of the activation energies and activation volumes from the low values for Et (5 kJ mol(-1) and 6 cm(3) mol(-1)) to the large values for PIB (55 kJ mol(-1) and 80 cm(3) mol(-1)) with increasing polymer content takes places in a pronounced sigmoidal manner.},
language = {English},
number = {3},
journal = {Journal of Supercritical Fluids},
author = {Mertsch, R. and Wolf, B. A.},
month = sep,
year = {1994},
keywords = {pressure, miscibility, viscosity, activation energy, activation volume, density, flow behavior, fractionation, moderately concentrated-solutions, polyisobutylene, supercritical ethylene},
pages = {165--169},
}
@article{schneider_solidification_1994,
title = {Solidification {Behavior} of the {Theta} {System} 2-{Propanol} {Poly}({N}-{Butyl} {Methacrylate}) .1. {Influences} of {Thermoreversible} {Gelation} on {Stationary} {Flow}},
volume = {33},
issn = {0035-4511},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1994&action=retrieve&mode=FullRecord},
doi = {Doi 10.1007/Bf00437300},
abstract = {Zero shear viscosities, eta0, were determined by means of a magnetoviscometer for melts of poly(n-butyl methacrylate) (M = 8.7 to 450 kg/mol, T = 53.5 to 200-degrees-C) and for concentrated solutions of the highest molecular weight sample in isopropanol (T = 34.8 to 131.5-degrees-C). Master curves can be constructed in both cases if the reference temperature is set proportional to the gelation temperature of the particular fluid. Special intersegmental interactions (eventually leading to thermoreversible gelation) can above all be felt in eta0 (T) and in M(c), the critical molecular weight determined in plots of log eta0 vs. log M. As the temperature is lowered, the behavior changes from WLF to Arrhenius, and M(c) declines considerably. The former observation is explained by analogy to the transition from fragile to hard glasses resulting from increased crosslinking. The latter effect can also be rationalized in terms of a physical network reducing the molecular weight that is required for the formation of entanglements.},
language = {English},
number = {3},
journal = {Rheologica Acta},
author = {Schneider, T. and Wolf, B. A. and Gahleitner, M.},
month = jun,
year = {1994},
keywords = {polymer solutions, cooccurrence, polymer-solutions, thermoreversible gelation, corresponding states, critical molecular weight, glass transition temperatures, glass-transition temperature, magnetoviscometer, master curves, polymer melts, principle, viscosity measurements, zero shear viscosity},
pages = {159--164},
}
@article{mertsch_solutions_1994,
title = {Solutions of {Poly}({Dimethylsiloxane}) in {Supercritical} {Co2} - {Viscometric} and {Volumetric} {Behavior}},
volume = {27},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1994&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00090a023},
abstract = {Homogeneous mixtures of five poly(dimethylsiloxane) fractions [23-74 kg/mol] with CO2 were studied (100-700 bar and 30-70-degrees-C) in the entire range of composition. An antoclave, which allows the determination of densities, was used to prepare the solutions. Viscosities eta were measured in a rolling-ball and in a Searle-type pressure apparatus, respectively, depending on the polymer content. For the lowest molar mass sample (the only one below the entanglement value) the viscosity of the mixtures is always less than that calculated on the basis of volume fractions from additivity of the eta values of the pure components. With all other fractions this is only so for large polymer contents; as these solutions are diluted, the deviations become positive where the effects increase with rising M. This complex behavior can be described quantitatively by means of only one (physically meaningful and molecular weight independent) adjustable parameter, if one uses surface fractions as the composition variable instead of volume fractions. The evaluation of eta(T) at constant p with respect to activation energies E(double dagger) and of eta(p) at constant T with respect to activation volumes V(double dagger) reveals a pronounced sigmoidal dependence of these parameters on the composition of the mixtures. For the pure polymer one extrapolates the following values in the limit of infinitely long chains: E(infinity)double dagger = 75 kJ/mol at 300 bar and V(infinity)double dagger = 43 cm3/mol at 30-degrees-C. The measured densities yield maximum excess specific volumes on the order of -10 Cm3/kg; these effects are almost 10 times larger than predicted by the Flory-Orwoll-Vrij theory.},
language = {English},
number = {12},
journal = {Macromolecules},
author = {Mertsch, R. and Wolf, B. A.},
month = jun,
year = {1994},
keywords = {flow behavior, fractionation},
pages = {3289--3294},
}
@article{wolf_continuous_1994-1,
title = {Continuous {Polymer} {Fractionation}},
volume = {6},
issn = {0935-9648},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1994&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/adma.19940060921},
abstract = {Continuous polymer fractionation (CPF) has been developed to provide access to large amounts of well-defined fractions where it is impossible to synthesize polymers with a narrow molecular weight distribution. The principle of CPF and some details of its implementation are presented. Examples of fractionations are reported, together with problems that can arise and their solutions. As there is a widespread need for uniform fractions, it is anticipated that CPF will become a routine operation.},
language = {English},
number = {9},
journal = {Advanced Materials},
author = {Wolf, B. A.},
month = sep,
year = {1994},
pages = {701--704},
}
@article{enders_interfacial-tension_1994,
title = {Interfacial-{Tension} and {Interaction} {Parameters}},
volume = {35},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1994&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0032-3861(05)80050-3},
abstract = {In view of various contradictory theoretical equations relating the interfacial tension sigma between phase-separated polymer solutions to the Flory-Huggins interaction parameter of the system, the idea that sigma should depend on the extent of the 'hump' in the concentration dependence of the Gibbs energy of mixing was studied. This investigation is based on 12 series of sigma(T) measurements reported in the literature and on additional experiments for the system cyclohexane/polystyrene. To quantify the extent of the 'hump', a reduced 'hump energy' epsilon was introduced and its value calculated for different temperatures from the measured critical data of the systems. The analysis of the entire experimental material yields a scaling law of the form sigma = E epsilon(F) where F is close to 0.5 for all systems, in contrast to E which varies within a larger interval. Furthermore, epsilon is related to tau, the relative distance to the critical temperature, by epsilon = A tau(B); B is approximately 2.4, again relatively independent of the system, in contrast to A. In case of trustworthy values of the scaling parameters, the above relations offer an interesting possibility to estimate sigma(T) from the sole knowledge of the critical temperature of the system.},
language = {English},
number = {26},
journal = {Polymer},
author = {Enders, S. and Huber, A. and Wolf, B. A.},
year = {1994},
keywords = {polymer solutions, interfacial tension, flory-huggins parameter, polymers},
pages = {5743--5747},
}
@article{horst_miscibility_1994,
title = {Miscibility {Behavior} for {Polymer} {Blends} in {Flow} - {Calculation} and {Comparison} with {Experiments}},
volume = {208},
issn = {0065-7727},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1994&action=retrieve&mode=FullRecord},
language = {English},
journal = {Abstracts of Papers of the American Chemical Society},
author = {Horst, R. and Wolf, B. A.},
month = aug,
year = {1994},
pages = {61--Pmse},
}
@article{tong_phase-equilibria_1995,
title = {Phase-{Equilibria} and {Interfacial}-{Tension} between {Coexisting} {Phases} for the {System} {Water} 2-{Propanol} {Poly}({Acrylic} {Acid})},
volume = {196},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1995&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.1995.021960208},
abstract = {The cloud point curve, tie-lines and interfacial tensions were measured for solutions of 50 mol-\% neutralized (counter-ion Na-circle plus) poly(arylic acid) (mass-average molar mass (M) over bar(w) = 9 700 g/mol; polydispersity index (M) over bar(w)/(M) over bar(w) = 2,0) in the mixed solvent water/2-propanol at 30 degrees C. Due to the non-uniformity of the polymer, the end-points of the tie-lines are not situated on the cloud-point curve. The interfacial tension sigma - determined by means of the spinning drop method - increases in sigmoidal manner with R(t1), the length of the tie-line, expressed in terms of weight fractions. An evaluation of these data in a double-logarithmic plot of sigma.M(-0,5) versus R(t1) yields a critical exponent of 4,23 as compared with 3,85 in the case of binary systems. The dependence of a on w(w), the over-all weight fraction of water in the mixture, can also be expressed as a power-law choosing (w(cw)-w(w))/w(cw) as the concentration variable (w(cw): critical weight fraction of water); for the present system the exponent of the resulting equation amounts to 2,33 as compared with 2,0 for toluene/polyisobutylene/poly(dimethylsiloxane).},
language = {English},
number = {2},
journal = {Macromolecular Chemistry and Physics},
author = {Tong, Z. and Meissner, K. and Wolf, B. A.},
month = feb,
year = {1995},
keywords = {continuous polymer fractionation, solvent},
pages = {521--527},
}
@article{petri_continuous_1995,
title = {{CONTINUOUS} {POLYMER} {FRACTIONATION} {OF} {POLY}({METHYL} {VINYL} {ETHER}) {AND} {A} {NEW} {KUHN}-{MARK}-{HOUWINK} {RELATION}},
volume = {196},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1995&action=retrieve&mode=FullRecord},
doi = {10.1002/macp.1995.021960508},
abstract = {Continuous polymer fractionation (CPF) - a new large-scale method - was applied to the technical poly(methyl vinyl ether) (PVME) using toluene as solvent and petroleum ether as nonsolvent. Two different devices served as fractionation apparatus, namely a column packed with glass beads and a set of mixer-settler extractors. Advantages and draw-backs of these devices are discussed. The experiments yielded numerous PVME fractions, varying in molar mass from 22 to 87 kg/mol and in molecular non-uniformity U = ((\\() over bar M(w) (\\)) over bar M(n)) - 1 from 0,25 to 0,41 according to gel-permeation chromatography as compared with ca. U = 1,30 for the starting material. The following Kuhn-Mark-Houwink relation was established for PVME in ethyl methyl ketone at 30 degrees C: [eta]/(mL/g) = 2,6 . 10(-3) (\$) over bar M(0,86).},
language = {English},
number = {5},
journal = {Macromolecular Chemistry and Physics},
author = {Petri, H. M. and Stammer, A. and Wolf, B. A.},
month = may,
year = {1995},
keywords = {pib, blend miscibility},
pages = {1453--1463},
}
@article{schneider_solidification_1995,
title = {Solidification {Behavior} of the {Theta}-{System} 2-{Propanol} {Poly}({N}-{Butyl} {Methacrylate}) .2. {Dynamic}-{Mechanical} {Studies} in the {Region} of {Gelation}},
volume = {34},
issn = {0035-4511},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1995&action=retrieve&mode=FullRecord},
doi = {Doi 10.1007/Bf00398437},
abstract = {Thermoreversible gelation of the system 2-propanol/poly (n-butyl methacrylate) - as detected by DSC or dielectric experiments - does not manifest itself in a straightforward manner in the dynamic-mechanical properties. Its occurrence can, however, be seen in many ways: i) For constant composition of the system and a reference temperature lower than T-gel, the storage modulus G' is larger than the loss modulus G'' in the glass transition zone of the master curve and both vary in an almost parallel manner with the angular frequency omega over almost two decades (whereas this feature is normally found for other gelling systems within the rubber plateau or the flow region). ii) The entanglement molecular weight obtained from G(max)'' is markedly less than the entanglement molecular weight in the melt divided by phi(2), the volume fraction of the polymer. iii) The temperature influences change from WLF-like to Arrhenius-like behavior as Tis lowered in the case of highly concentrated polymer solutions; analogous considerations hold true as phi(2) is increased at constant T. iv) For sufficiently low temperatures, the activation energy of flow exhibits a maximum in the concentration range where the gelation is - according to DSC experiments - most pronounced. Like with ordinary non-gelling systems it is possible to construct master curves. On the basis of Graessley's theory identical dependencies are obtained for the variation of the entanglement parts of the stationary viscosity with shear rate and for the dependence of the entanglement part of the complex viscosity on the frequency omega of oscillation. Zero shear viscosity and limiting value of the complex viscosity for vanishing omega as a function of phi(2) match smoothly and exhibit two points of inflection.},
language = {English},
number = {2},
journal = {Rheologica Acta},
author = {Schneider, T. and Wolf, B. A.},
month = apr,
year = {1995},
keywords = {dependence, flow, cooccurrence, polymer-solutions, viscosity, thermoreversible gelation, 2-propanol, activation energies of flow, concentration and temperature influences, entanglement molecular weights, gel point, glass transition, loss modulus, network type, poly(n-butyl methacrylate), rheology, storage modulus, thermodynamic conditions, viscoelasticity},
pages = {172--181},
}
@article{haberer_continuous_1995,
title = {Continuous {Fractionation} of {Poly}({Acrylic} {Acid})},
volume = {228},
issn = {0003-3146},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1995&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/apmc.1995.052280114},
abstract = {45 g of poly(acrylic acid) (PAA 500) with a trimodal molar mass distribution ((M) over bar(w) = 500 kg/mol, ((M) over bar(w)/(M) over bar(n)) - 1 = 2.33) were fractionated by means of CPF (continuous polymer fractionation) in two steps using 1,4-dioxane as solvent. The counter-current extraction was performed in a glass column (length: 190 cm, diameter: 1.5 cm) filled with a network of wires, introducing the feed 75 cm from its upper end. The distribution of the highest molar mass fraction ((M) over bar(w) = 760 kg/mol) is unimodal and comparatively narrow ((M) over bar(w)/(M) over bar(n)) - 1 = 0.66). Indications exist that fractionation is not only taking place with respect to molar mass but also with respect to tacticity.},
language = {English},
journal = {Angewandte Makromolekulare Chemie},
author = {Haberer, M. and Wolf, B. A.},
month = jun,
year = {1995},
pages = {179--184},
}
@article{schultes_continuous_1995,
title = {Continuous {Fractionation} of {Poly}[({Dimethylimino}){Decamethylene} {Bromide}] and {Molecular}-{Weight} {Dependence} of the {Glass}-{Transition}},
volume = {196},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1995&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.1995.021960403},
abstract = {30 g of the ionene poly[(dimethylimino)decamethylene bromide] were fractionated by a continuous counter-current extraction method (CPF) using ethylene glycol monoethyl ether as the solvent and diisopropyl ether as the non-solvent component. The efficiency of the separation was checked by viscometry and gel-permeation chromatography (GPC) measurements. Eight fractions of different molar mass were prepared for differential scanning calorimetry (DSC) experiments. With bromide as counter-ion, the glass transition temperature of the ionene increases from ca. 60 to 85 degrees C as the intrinsic viscosity of this material (in 0,4 M aqueous solutions of KBr at 25 degrees C) rises from ca. 14 to 22 mL/g. When bromide is replaced by tetrafluoroborate, the glass transition temperature remains almost constant at ca. 60 degrees C, irrespective of the molar mass of the ionene.},
language = {English},
number = {4},
journal = {Macromolecular Chemistry and Physics},
author = {Schultes, K. and Wolf, B. A. and Meyer, W. H. and Wegner, G.},
month = apr,
year = {1995},
keywords = {continuous polymer fractionation, polyelectrolytes},
pages = {1005--1016},
}
@article{petri_composition-dependent_1995,
title = {Composition-{Dependent} {Flory}-{Huggins} {Parameters} - {Molecular}-{Weight} {Influences} at {High}-{Concentrations}},
volume = {196},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1995&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.1995.021960719},
abstract = {Flory-Huggins interaction parameters chi were determined by means of equilibrium vapor pressures (measured via a combination of a head space sampler with a gas chromatograph) and light scattering as a function of composition and temperature for the systems cyclohexanone/polystyrene [CHO/PS] and cyclohexanone/poly(butyl methacrylate) [CHO/PBMA]. The investigation of molecular weight influences on chi with the system CHO/PBMA demonstrates that they persist almost up to the pure polymer. In order to rationalize this result, it is postulated (in accord with experimental findings and theoretical predictions) that the dimensions of polymer chains may vary upon the addition of solvent even in highly concentrated solutions. From the information concerning chi (T) the interaction parameters were split into their enthalpy and entropy part. In the case of CHO/PS these quantities vary considerably with composition and turn out to be linearly interrelated.},
language = {English},
number = {7},
journal = {Macromolecular Chemistry and Physics},
author = {Petri, H. M. and Wolf, B. A.},
month = jul,
year = {1995},
keywords = {cooccurrence, polymer-solutions, thermoreversible gelation},
pages = {2321--2333},
}
@article{horst_calculation_1995,
title = {Calculation of phase diagrams not requiring the derivatives of the {Gibbs} energy demonstrated for a mixture of two homopolymers with the corresponding copolymer},
volume = {4},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1997&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0032-3861(96)01076-2},
abstract = {A method is presented which allows the calculation of phase diagrams (spinodal, binodal and tie lines) on the basis of the Gibbs energy of mixing Delta G. No derivatives of Delta G with respect to the composition variables are required. This method is particularly useful in cases where the composition dependence of Delta G is very complex and no analytical representation of the derivatives can be given. The method is applied to a ternary mixture of two homopolymers with a copolymer consisting of the same monomers. The sequence distribution of the copolymer is kept constant between random and purely alternating, and phase diagrams are calculated for different chemical compositions of the copolymer. The complex phase separation behavior resulting for a 1:1 copolymer becomes much simpler as one monomeric unit starts to predominate in the copolymer.},
language = {English},
journal = {Macromolecular Theory and Simulations},
author = {Horst, Roland},
year = {1995},
pages = {449--458},
}
@article{enders_interfacial-tension_1995,
title = {Interfacial-{Tension} of {Phase}-{Separated} {Polymer}-{Solutions} and {Relation} to {Their} {Equation} of {State}},
volume = {103},
issn = {0021-9606},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1995&action=retrieve&mode=FullRecord},
doi = {Doi 10.1063/1.470059},
abstract = {Using an effective (coarse-grained) thermodynamic potential describing the excess free energy of mixing of a polymer solution and fitting its parameters to measured critical point data, we obtain the ''hump'' epsilon(tau) of this potential in the two-phase region (tau being the reduced distance from the critical temperature T of unmixing). For 30 different systems (varying the degree of polymerization r as well as choosing different polymer-solvent pairs) it is shown that the data are reasonably well represented by a power law, epsilon(tau)=epsilon(tau)tau(zeta). While mean field theory implies zeta=5/2 and scaling theory zeta=3 nu+beta approximate to 2.22 (using Ising model exponents nu approximate to 0.63,beta approximate to 0.325), the ''effective'' exponent extracted from the data mostly falls in between these limits (zeta(eff)approximate to 2.4). since the interfacial tension satisfies a similar power law, sigma(tau)=sigma,tau tau(mu) (with mu=3/2 in mean field theory or mu=2 nu approximate to 1.26 in scaling theory), we also consider a relation between interfacial tension and free energy hump, sigma(epsilon)=sigma(epsilon)epsilon(phi). While mean-field theory implies phi=3/5 and scaling theory phi=2(3+beta/nu)approximate to 0.57, the empirical exponent lies in the range 0.5 less than or similar to phi(eff)less than or similar to 0.6. we present estimates of molecular weight dependencies of critical amplitude prefactors epsilon(tau)sigma(tau)sigma(epsilon) and of related quantities for many different systems. We also discuss whether the critical amplitude combination (epsilon(tau)/B-tau)(2/3)/sigma, where B-tau describes the coexistence curve {phi(coex)((2))-phi(coex)((1))=(\$) over cap B(tau)tau(beta)} is universal. Contrary to some theoretical expectations, our data imply that this combination is not universal, and hence it cannot be used to predict interfacial tensions from equation of state data. (C) 1995 american Institute of Physics.},
language = {English},
number = {9},
journal = {Journal of Chemical Physics},
author = {Enders, S. and Wolf, B. A. and Binder, K.},
month = sep,
year = {1995},
keywords = {critical exponents, critical-point, fluids, universal coexistence curve},
pages = {3809--3819},
}
@article{petri_hitherto_1995,
title = {Hitherto {Ignored} {Effects} of {Chain}-{Length} on the {Flory}-{Huggins} {Interaction} {Parameters} in {Concentrated} {Polymer}-{Solutions}},
volume = {28},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1995&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma00118a027},
abstract = {Equilibrium vapor pressures were measured for the systems toluene/poly(dimethylsiloxane) [two different polymers, 35-55 degrees C] and cyclohexane/poly(vinyl methyl ether) [three polymers, 35-65 degrees C] by combining a head-space sampler with a gas chromatograph. The Flory-Huggins interaction parameters chi calculated therefrom as a function of the volume fraction phi(2) of polymer were complemented by literature data on inverse gas chromatography and by chi values at high dilution from osmometry in the former case and from light-scattering measurements in the latter. These results demonstrate that the effects of differing chain lengths can still be felt at phi(2) {\textgreater} 0.5, in contrast to the general perception. This observation is tentatively explained in terms of changes in coil dimension taking place in the region of high polymer concentrations. Furthermore, chi(phi(2)) may exhibit a minimum even with the common polymers of present interest. In all cases the concentration dependence of chi is described well by a series expansion of chi with respect to phi(2) up to the fourth term, if two parameters are adjusted. The temperature dependence of chi at different concentrations demonstrates that the heats of dilution generally increase with increasing phi(2), whereas the noncombinatorial entropy of dilution decreases. This situation leads to a linear interdependence of the enthalpy and entropy part of chi. With the system toluene/poly(dimethylsiloxane) one observes an inversion of the heat effects upon an increase of phi(2) from exothermal to endothermal at ca. 13 vol \%.},
language = {English},
number = {14},
journal = {Macromolecules},
author = {Petri, H. M. and Schuld, N. and Wolf, B. A.},
month = jul,
year = {1995},
keywords = {polystyrene, thermodynamics, blends, chromatography, concentration-dependence, poly(vinyl methyl-ether), polydimethylsiloxane-solutions},
pages = {4975--4980},
}
@article{horst_phase-diagrams_1995,
title = {Phase-{Diagrams} {Calculated} for {Quaternary} {Polymer} {Blends}},
volume = {103},
issn = {0021-9606},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1995&action=retrieve&mode=FullRecord},
doi = {Doi 10.1063/1.470708},
abstract = {A method is presented that allows the calculation of phase diagrams (spinodal, binodal, and tie lines) of quaternary mixtures on the basis of the Gibbs energy of mixing Delta G. No derivatives of Delta G with respect to the composition variables are required. This method is particularly useful in cases where the composition dependence of Delta G is very complex, and no analytical representation of Delta G can be found. Phase diagrams have been calculated on the basis of the Flory-Huggins theory for mixtures of four polymers. Blends that phase separate because of very favorable interactions (negative interaction parameters) were of particular interest. In this case miscibility gaps can be located inside the tetrahedron composed of the Gibbs phase triangles of the four completely miscible ternary subsystems. For symmetrical mixtures of K components (identical chain lengths and interaction parameters) equations are presented that allow the calculation of K-phase and (K - 1)-phase regions for any value of K. (C) 1995 American Institute of Physics.},
language = {English},
number = {9},
journal = {Journal of Chemical Physics},
author = {Horst, R. and Wolf, B. A.},
month = sep,
year = {1995},
keywords = {equilibria},
pages = {3782--3787},
}
@article{schultes_continuous_1995-1,
title = {Continuous {Fractionation} of an {Ionene} {Containing} {Cycloaliphatic} {Moieties} and the {Dependence} of the {Glass}-{Transition} {Temperature} on {Molar}-{Mass}},
volume = {46},
issn = {0323-7648},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1995&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/actp.1995.010460503},
abstract = {About 340 g of a cycloaliphatic ionene (see formula given in the introduction) were fractionated by a continuous countercurrent extraction method (CPF). The efficiency of the separation was checked by viscometry and gel permeation chromatography (GPC). Ten different fractions with number average molecular masses between 16 000 and 29 000 D were obtained and their glass transition temperatures T-g determined by differential scanning calorimetry (DSC) for their bromide and tetrafluoroborate salts. No molecular weight dependence of T-g was found, in contrast to recently reported results with aliphatic ionenes, where - in case of the bromide - T-g increases with rising molecular weight.},
language = {English},
number = {5},
journal = {Acta Polymerica},
author = {Schultes, K. and Wolf, B. A. and Meyer, W. H. and Wegner, G.},
month = oct,
year = {1995},
keywords = {polyelectrolytes},
pages = {367--372},
}
@article{horst_calculation_1996,
title = {Calculation of critical points not requiring the derivatives of the {Gibbs} energy demonstrated for a mixture of two homopolymers with the corresponding copolymer},
volume = {5},
issn = {1022-1344},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1996&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/mats.1996.040050106},
abstract = {The method for the calculation of phase diagrams (spinodal, binodal and tie lines) exclusively on the basis of the Gibbs energy of mixing, Delta G, with no need of calculating its derivatives with respect to the composition variables was extended to determine the critical conditions and the condition of the stability of the critical points. The method is applied to a ternary mixture of two homopolymers with a copolymer consisting of the same monomers. The sequence distribution of the copolymer is kept constant between random and purely alternating, and phase diagrams are calculated for different chemical compositions of the copolymer. Three critical lines were found within a very small interval of the copolymer composition.},
language = {English},
number = {1},
journal = {Macromolecular Theory and Simulations},
author = {Horst, R. and Wolf, B. A.},
month = jan,
year = {1996},
keywords = {phase-separation, systems},
pages = {81--92},
}
@article{petri_determination_1996,
title = {Determination of interaction parameters for highly incompatible polymers},
volume = {37},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1996&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/0032-3861(96)87632-4},
abstract = {Experiments and calculations were performed for the ternary system cyclohexane/polystyrene/polyisobutylene (CH/PS/PIB) to study the possibilities of determining the Flory-Huggins interaction parameters chi(PS/PIB) between these highly incompatible polymers. To that end chi(CH/PIB) was determined (vapour pressure measurements and additional thermodynamic information) as a function of composition; chi(CH/PS) and its concentration dependence could be taken from earlier experiments. Furthermore, the cloud point curve and some tie lines of the ternary system were measured. In the subsequent evaluation of these data, the phase diagram was calculated and chi(PS/PIB) (as a function of concentration) adjusted until the theoretically calculated binodal line matches with the measured cloud points. The polymer/polymer interaction parameter thus obtained increases at 35 degrees C from 0.416 in the limit of pure PS to 0.449 in the limit of pure PIE. This result agrees reasonably well with the prediction of the solubility parameter theory and is in good accord with information stemming from light scattering experiments in a ternary system under 'optical theta conditions'. Copyright (C) 1996 Elsevier Science Ltd.},
language = {English},
number = {13},
journal = {Polymer},
author = {Petri, H. M. and Horst, R. and Wolf, B. A.},
month = jun,
year = {1996},
keywords = {compatibility, gas-liquid-chromatography, light-scattering, phase-equilibrium, ternary-systems},
pages = {2709--2713},
}
@article{enders_influence_1996,
title = {Influence of molar mass distribution on the compatibility of polymers},
volume = {A33},
issn = {1060-1325},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1996&action=retrieve&mode=FullRecord},
doi = {Doi 10.1080/10601329608010907},
abstract = {Phase equilibria were calculated by means of a new method (direct minimization of the Gibbs energy of mixing) for polymer blends consisting of monodisperse polymer A and polydisperse polymer B. The results obtained for a Schulz-Flory distribution of B (molecular nonuniformity U = (M(w)/M(n)) - 1 = 1 and 100 components of model B) agree quantitatively with that of computations on the basis of continuous thermodynamics. The influence of U-B on the miscibility of A and B in 1:1 mixtures was studied for constant M(w) of B, quantifying the incompatibility of the polymers by the length of the tie lines. The outcome of these calculations demonstrates that the typical effect of an augmentation of U-B (keeping M(w) and the overall composition constant) consists in an enlargement of the mutual solubility of A and B. However, for an almost compatible pair of polymers (i.e., interaction parameters g are only slightly larger than the critical values for U-B = 0), this statement remains true only in the case of sufficiently small U-B. In order to gain some understanding of these findings, calculations were also performed for ternary systems (A and two species B). They demonstrate that it is the distance of the overall composition in the Gibbs phase triangle to the critical line (connecting the critical points for different U-B) which governs the changes in compatibility. Normally the critical point comes closer to the overall composition as U-B is raised, except for low g values where the critical point - after an initial approach - drifts apart as U-B becomes larger.},
language = {English},
number = {8},
journal = {Journal of Macromolecular Science-Pure and Applied Chemistry},
author = {Enders, S. and Hinrichs, A. and Horst, R. and Wolf, B. A.},
year = {1996},
keywords = {phase-separation, interfacial-tension, blends},
pages = {1097--1111},
}
@article{enders_phase_1996,
title = {Phase separation of blends of polydisperse polymers: {Comparison} between experiment and theory for the system poly(dimethylsiloxane)/poly(ethylmethylsiloxane)},
volume = {197},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1996&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.1996.021970928},
abstract = {Cloud point curves were measured turbidimetrically for blends (upper critical solution temperatures; UCSTs) of poly(ethylmethylsiloxane) (PEMS) and four different samples of poly(dimethylsiloxane) (PDMS); the weight average molar masses in kg/mol are 31.2 for PEMS and 10.4, 15.5, 18.1 and 24.0 for PDMS; all components have polydispersity indices D (= (M) over bar(w)/(M) over bar(n)) within the range from 1.82 to 2.67. Corresponding calculations on the basis of the Flory-Huggins theory (three adjustable parameters) account for the polydispersity; molecular weight distributions are represented by the generalized Schulz-Flory equation. Calculated cloud point curves agree very well with those measured, if individual sets of parameters are admitted for each of the different mixtures. Even for an identical set of parameters the maximum deviations remain moderate. Realistic model calculations concerning the influences of D on cloud points and on critical points were performed with this set of parameters. For the present (only slightly endothermal) system, the precipitation threshold increases from 318 to 558.6 K as D-PEMS is raised from 1.87 to 4.00, keeping the number average degree of polymerization constant.},
language = {English},
number = {9},
journal = {Macromolecular Chemistry and Physics},
author = {Enders, S. and Stammer, A. and Wolf, B. A.},
month = sep,
year = {1996},
keywords = {dependence, polystyrene, miscibility, diagrams, interaction parameter, molecular-weight},
pages = {2961--2972},
}
@article{horst_phase_1996,
title = {Phase behavior of the ternary system water / hydroxyethyl cellulose / nonionic surfactant},
volume = {274},
abstract = {The phase behavior of ternary aqueous solutions of two samples of hydroxyethyl cellulose (HEC) and oligoethylene glycol mono(n-alkyl) ethers C(x)E(y) (x: 11; y: 28, 40) at 25 degrees C has been studied above the CMC of C(x)E(y). The influence of molar mass of HEC and the number of ethylene glycol units on the phase diagram has been investigated. Both binary systems water/HEC and water/C(x)E(y) are completely miscible. The ternary mixture of water/polymer/nonionic surfactant is homogeneous if the weight fraction of water is larger than 0.93, or else it can separate segregatively, i.e., HEC is enriched in one phase, the surfactant in the other. The theoretical description is based on an equation for the Gibbs energy of mixing which takes polar conformations into account. The phase diagrams are calculated by means of a new method which does not require the derivatives of the Gibbs energy of mixing.},
journal = {Colloid and Polymer Science},
author = {Horst, Roland and Gerharz, B.},
year = {1996},
pages = {439--445},
}
@article{horst_calculation_1996-1,
title = {Calculation of phase diagrams not requiring the derivatives of the {Gibbs} energy for multinary mixtures},
volume = {5},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1996&action=retrieve&mode=FullRecord},
doi = {10.1021/ma960835n},
abstract = {A method for the calculation of phase diagrams (tie lines and binodal, spinodal, critical points and their stability) based exclusively on the Gibbs energy of mixing with no need of its derivatives with respect to the composition variables is extended to multinary mixtures for any number of components. The mathematical description of the (K-1)-dimensional phase diagram of a K-component mixture is presented. The method is demonstrated for a quinternary blend of five polymers exhibiting a closed miscibility gap; all binary, ternary and quaternary subsystems are completely miscible. The phase separation in the quinternary system is caused by very favorable interactions in the ternary subsystem 1/2/3 and the binary subsystem 4/5.},
language = {English},
journal = {Macromolecular Theory and Simulations},
author = {Horst, Roland},
year = {1996},
pages = {789--800},
}
@article{krause_shear_1997,
title = {Shear effects on the phase diagrams of solutions of highly incompatible polymers in a common solvent .1. {Equilibrium} behavior and rheological properties},
volume = {30},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1997&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma9609745},
abstract = {Phase diagrams (cloud points, tie lines, critical compositions) and viscosities of homogeneous solutions were determined at temperatures ranging from 20 to 100 degrees C for three representatives of the ternary system cyclohexanone/polystyrene/poly(n-butyl methacrylate) [CHO/PS/PBMA] in preparation of a study on shear influences. An only moderate increase of the two-phase region observed upon heating (LCST behavior) witnesses little heat effects upon mixing. Tie lines which are nearly parallel to the PS/PBMA edge of the Gibbs phase triangle indicate comparable solvent quality of CHO for both polymers. The quantitative mathematical description of the equilibrium behavior-required for a theoretical treatment of shear influences-was performed on the basis of the Flory-Huggins equation by means of composition and temperature dependent binary (integral) interaction parameters g(ij). The present approach avoids the use of chemical potentials and minimizes the Gibbs energy of mixing directly. Experimental data for g(CHO/PS) and g(CHO/PBMA) were available from earlier work; g(PS/PBMA) was adjusted to reproduce the measured phase diagram of the ternary system. Calculated and measured phase diagrams match very well. The rheological results were used to establish a mathematical expression describing the composition and temperature dependence of the solution viscosities; such an equation is required for the theoretical treatment of shear influences on the phase diagram.},
language = {English},
number = {4},
journal = {Macromolecules},
author = {Krause, C. and Wolf, B. A.},
month = feb,
year = {1997},
keywords = {systems, thermodynamics, blends},
pages = {885--889},
}
@article{krause_shear_1997-1,
title = {Shear effects on the phase diagrams of solutions of highly incompatible polymers in a common solvent .2. {Experiment} and theory},
volume = {30},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1997&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma9609442},
abstract = {Cloud point temperatures (T-cp) were measured at different constant shear rates for three representatives of the ternary system cyclohexanone/polystyrene/poly(n-butyl methacrylate) (CHO/PS/PBMA) by means of a newly constructed rheo-optical apparatus that can be operated in the temperature range from 0 to 100 degrees C up to maximum shear rates of 1440 s(-1) and maximum stresses of 384 Pa. In all cases one observes an extension of the homogeneous region as the shear rate gamma is raised. With the system CHO/PS 196w/PBMA 2050 (the figures denote the molar masses of the polymers in kilograms/mole) the effects become maximum for high concentrations of PBMA, where the demixing temperatures increase by more than 25 degrees C per 100 s(-1). For a pronounced predominance of one polymer in the mixture, T-cp is a linear function of gamma in the entire range of shear rates. At blend compositions in between, the slope of T-cp versus gamma is largest at the lowest shear rates and diminishes as gamma is increased until the dependence becomes linear again at sufficiently large values. Possible effects of polymolecularity were studied by exchanging the broadly distributed PS 196w against the narrowly distributed PS 207; no differences beyond experimental error could be detected. A substitution of the high molecular weight PBMA 2050 by the lower molecular PBMA 335 leads to a pronounced reduction of the effects; in this case the extent of shear-induced mixing passes a minimum for a blend composition of approximately 1:1. Phase diagrams of the flowing systems of interest were also calculated theoretically on the basis of a generalized Gibbs energy of mixing (value for stagnant solutions plus energy stored under stationary conditions in the sheared state) by direct minimization of this quantity. The information concerning equilibrium and rheological behavior required for that purpose was obtained as described in part 1 of this series. The sign and magnitude of all theoretically predicted effects plus their variation with molar masses and composition are in very good agreement with the experimentally observed features of shear-induced changes of the phase state. Possible reasons for the lack of complete quantitative agreement are discussed.},
language = {English},
number = {4},
journal = {Macromolecules},
author = {Krause, C. and Horst, R. and Wolf, B. A.},
month = feb,
year = {1997},
keywords = {flow, blends},
pages = {890--895},
}
@article{horst_calculation_1996-2,
title = {Calculation of miscibility behavior of multinary polymer blends},
volume = {112},
issn = {1022-1360},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1996&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/masy.19961120107},
abstract = {A method for the calculation of phase diagrams (tie lines and binodal, spinodal, critical points and their stability) based exclusively on the Gibbs energy of mixing, Delta G, is presented which does not require the calculation of the derivatives with respect to the composition. The method is demonstrated for ternary mixtures of two homopolymers and the corresponding copolymer, and for quaternary and quinternary blends of five polymers exhibiting a closed miscibility gap. The advantages of the presented method become most obvious in the mathematical description of measured phase diagrams, where complex composition dependencies of the interaction parameter are observed.},
language = {English},
journal = {Macromolecular Symposia},
author = {Horst, R. and Wolf, B. A.},
month = dec,
year = {1996},
keywords = {critical solution temperatures},
pages = {39--46},
}
@article{an_application_1997,
title = {Application of the {Sanchez}-{Lacombe} lattice fluid theory to the system pvme/ps and model calculations},
volume = {A34},
issn = {1060-1325},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1997&action=retrieve&mode=FullRecord},
doi = {Doi 10.1080/10601329708010032},
abstract = {Cloud point curves reported in the literature for five representatives of the system poly(vinyl methyl ether)/polystyrene were evaluated theoretically by means of the Sanchez-Lacombe lattice fluid theory. The measured phase separation behavior can be described within experimental error using only one adjustable parameter (quantifying the interaction between the unlike mers). The Flory-Huggins interaction parameters calculated from this theoretical description depend in good approximation linearly on composition (volume fractions) and on the inverse temperature. An evaluation of these data yields a maximum heat effect which is almost one order of magnitude less (ca. -0.25 J/cm(3)) than obtained via Hess's cycle (dissolution of the components and of the blend) from calorimetric measurements. Model calculations on the basis of the present theory demonstrate that the critical points shift to a different extent upon a certain relative change in the molar mass of the blend components. The sensitivity of the calculated phase diagrams against changes in the scaling parameter decreases in the following order: interaction energies between unlike mers, differences in the scaling temperatures, pressures and densities.},
language = {English},
number = {9},
journal = {Journal of Macromolecular Science-Pure and Applied Chemistry},
author = {An, L. J. and Wolf, B. A.},
year = {1997},
keywords = {polystyrene, polyvinyl methyl-ether), miscibility, temperature, polymer blends, state, thermodynamics, poly(vinyl methyl-ether), equation, liquids},
pages = {1629--1644},
}
@article{wolf_improvement_1997,
title = {Improvement of polymer solubility: {Influence} of shear and of pressure},
volume = {69},
issn = {0033-4545},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1997&action=retrieve&mode=FullRecord},
doi = {DOI 10.1351/pac199769050929},
abstract = {Polymer solutions and liquid polymer mixtures are in their phase-separation very sensitive to shear, in contrast to low molecular weight systems. Shear-induced changes of the demixing temperature up to 100 degrees C can be observed. The reason for this behavior lies in the ability of macromolecules to store energy in the stationary state while the system flows. Measurements with polymer solutions and with polymer blends reveal a multitude of phenomena. All experimental results can be rationalized at least semi-quantitatively on the basis of a theoretical approach using a generalized Gibbs energy of mixing containing the stored energy. Pressure induced changes in the demixing conditions for polymer solutions turn out: to be rather different for systems which phase separate upon cooling or upon heating. In the former case (UCSTs) the effects are small (typically +/- 1-2 K/100 bar), vary in sign and are hard to predict theoretically. In the latter case pressure practically always enhances miscibility and the effects are considerably larger (typically + 100-200K/100 bar). Theories based on the corresponding states principle yield reasonable forecasts for the behavior of such solutions.},
language = {English},
number = {5},
journal = {Pure and Applied Chemistry},
author = {Wolf, B. A.},
month = may,
year = {1997},
keywords = {flow, phase-separation, miscibility, blends},
pages = {929--933},
}
@article{jorzik_reduction_1997,
title = {Reduction of the interfacial tension between poly(dimethylsiloxane) and poly(ethylene oxide) by block copolymers: {Effects} of molecular architecture and chemical composition},
volume = {30},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1997&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma9613300},
abstract = {Interfacial tensions sigma were measured by means of the sessile drop method for mixtures of poly(ethylene oxide) [PEO, M-w = 41 kg/mol] with five samples of poly(dimethylsiloxane)s [PDMS, M-w ranging from 4 to 177 kg/mol] in the temperature interval 70-130 degrees C. Within experimental error sigma does not depend on T and the influences of molar mass can be well described by a linear dependence on M-n(-2/3). The ability of block copolymers to reduce sigma when added in small amounts was studied for two families of these substances. With type I all blocks are made of either DMS or EO and the members differ in the molecular architecture only (diblocks, triblocks, and ''bottle-brushes''). Type II comprises diblock copolymers, and the members differ in the chemical composition of the blocks which consist of EO, styrene, or methyl methacrylate. The reduction of sigma upon an increase in x(add), the base mole fraction of the additive in the PEO phase, is substantial for all additives under consideration; it can be well described by an equation of Tang-Huang containing two characteristic parameters: sigma(s), the saturation interfacial tension approached in the limit of large x(add), and x(char), the additive concentration required to achieve Ile of the maximum reduction. In the case of type I block copolymers, upsilon, the total number of DMS segments, turns out to be more decisive for their efficiency than their architecture, in contrast to the theoretical expectation. A lower limit of sigma(s) congruent to 1 mN/m is reached for upsilon {\textgreater} 30. At least the present representatives of type II additives are less efficient than those of type I; an increase in the number of segments does not change sigma(s), in a noteworthy way, whereas there exist indications that it reduces x(char).},
language = {English},
number = {16},
journal = {Macromolecules},
author = {Jorzik, U. and Wolf, B. A.},
month = aug,
year = {1997},
keywords = {polymer blends, weight},
pages = {4713--4718},
}
@article{horst_calculation_1997,
title = {Calculation of vapor pressures not requiring the derivatives of the energy of mixing},
volume = {6},
abstract = {A method is presented for the calculation of vapor pressures exclusively on the basis of the energy of mixing, the knowledge of chemical potentials is not required. The only condition used for the calculation is the minimum of the energy of mixing of the overall system in equilibrium. The gas phase is treated as an ideal gas, for the liquid phase no specific thermodynamic description is assumed. The method is demonstrated for a mixture of two solvents and one polymer. The system water/poly(ethylene oxide), the thermodynamics of which are described by an equation that can only be solved numerically thus impeding the calculation of chemical potentials, serves as an example. Interaction parameters are determined by fitting calculated vapor pressures to literature data.},
journal = {Macromolecular Theory and Simulations},
author = {Horst, Roland},
year = {1997},
pages = {427--435},
}
@article{barth_vapour_1998,
title = {({Vapour} plus liquid) equilibria of (water plus dimethylformamide): application of the headspace gas chromatography for the determination of thermodynamic interactions},
volume = {30},
issn = {0021-9614},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000074195300008&action=retrieve&mode=FullRecord},
doi = {DOI 10.1006/jcht.1997.0333},
abstract = {Isothermal measurements of the partial vapour pressures have been carried out on {water + dimethylformamide (DMF)} at temperatures between T = 305.15 K and T = 323.15 K using an apparatus composed of a headspace sampler and a normal gas chromatograph. These data were simultaneously evaluated in one step with respect to the (composition dependent, integral) Flory-Huggins interaction parameter g by means of a new method which minimizes the Gibbs energy of mixing and does not require chemical potentials. The expression for g given by Koningsveld and Kleintjens, originally designed for polymer solutions, describes the present results best. (C) 1998 Academic Press Limited.},
language = {English},
number = {5},
journal = {Journal of Chemical Thermodynamics},
author = {Barth, C. and Horst, R. and Wolf, B. A.},
month = may,
year = {1998},
keywords = {polymer-solutions, (vapour + liquid) equilibria, (water + dimethylformamide), flory-huggins interaction parameter, gibbs energy of mixing, headspace gas chromatography, interaction parameters},
pages = {641--652},
}
@article{an_pressure_1997,
title = {Pressure dependence of the miscibility of poly(vinyl methyl ether) and polystyrene: {Theoretical} representation},
volume = {107},
issn = {0021-9606},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1997&action=retrieve&mode=FullRecord},
doi = {Doi 10.1063/1.474571},
abstract = {The present calculations were performed on the basis of the Sanchez-Lacombe-Balasz lattice fluid theory. The two system specific parameters epsilon(12) and delta epsilon required for that purpose have been obtained from the spinodal temperatures measured (SANS) for mixtures of poly(vinyl methyl ether) (PVME) and deuterated polystyrenes (d-PS) by Schwahn and coworkers. The experimental data reported for atmospheric pressure and six representatives of the present system are well described theoretically, where epsilon(12) does not depend on molar mass and delta epsilon decreases only slightly as the chain length of d-PS is raised. The measured pressure influences on the spinodal conditions correspond to an approximately linear reduction of delta epsilon* with increasing P; this observation should reflect the volume changes associated with the formation of specific interactions. According to the present calculations the critical composition shifts markedly towards pure PVME as P is raised. Since experimental data are commonly expressed in terms of the Flory-Huggins theory, the current results were also translated into Flory-Huggins interaction parameters and evaluated with respect to the contributions of enthalpy and of entropy. The agreement between experimental information and that calculated from the Sanchez-Lacombe-Balasz lattice fluid theory is reasonable. (C) 1997 American Institute of Physics.},
language = {English},
number = {7},
journal = {Journal of Chemical Physics},
author = {An, L. J. and Horst, R. and Wolf, B. A.},
month = aug,
year = {1997},
keywords = {polymer blends, scattering, state, thermodynamics, phase-diagrams},
pages = {2597--2602},
}
@article{meissner_continuous_1998,
title = {Continuous polymer fractionation: {How} does it function and how can it be applied to celluloses?},
volume = {52},
issn = {0031-1340},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000077865700012&action=retrieve&mode=FullRecord},
abstract = {For basic research as well as for some technical applications it is often mandatory to have access to sufficient amounts of polymers with narrow molecular weight distribution. In case such products cannot be synthesized they must be obtained by fractionation. A method called CPF (Continuous Polymer Fractionation) allows the separation of the starting materials in their short chain and in their long chain constituents on a technical scale. This procedure consists in a continuous counter-current extraction; its successive application yields products with desired molecular weights and molecular weight distributions. So far CPF has been successfully applied to approximately two dozens of synthetic polymers. Cellulose, however could up to now only be fractionated in its derivatized form. Hydroxyethylcellulose did not show any particular difficulties. To prepare cellulose with narrow molecular weight distribution, CPF was also performed with trimethylsilylcellulose (where the substituents can be easily removed); here, however it turned out necessary to overcome several problems which are particularities of the system. In order to get easier access to such products we are presently checking whether there exist mixed solvents for cellulose which are suited for CPF.},
language = {German},
number = {12},
journal = {Papier},
author = {Meissner, K. and Wolf, B. A.},
month = dec,
year = {1998},
keywords = {dependence, glass-transition},
pages = {749--753},
}
@article{schneider_interfacial_1997,
title = {Interfacial tension of demixed polymer solutions: augmentation by polymer additives},
volume = {18},
issn = {1022-1336},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=1997&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/marc.1997.030180705},
abstract = {The interfacial tension between phase separated polymer solutions increases pronouncedly upon the addition of small amounts of incompatible polymers. This feature is demonstrated by means of measurements with solutions of polystyrene in cyclohexane and the following additives: poly(styrene-block-dimethylsiloxane), polyisobutylene and polydimethylsiloxane. Theoretical considerations based on a correlation between the lengths of tie lines and the corresponding interfacial tension corroborate this finding.},
language = {English},
number = {7},
journal = {Macromolecular Rapid Communications},
author = {Schneider, A. and Wolf, B. A.},
month = jul,
year = {1997},
keywords = {blends},
pages = {561--567},
}
@article{an_combined_1998,
title = {Combined effects of pressure and shear on the phase separation of polymer solutions},
volume = {31},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000074853700029&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma970723b},
abstract = {Experimental information available in the literature on the phase separation behavior of the system trans-decalin/polystyrene as a function of pressure and shear rate ibr different molar masses M of the polymer was used to check to which extent the effects of these two variables can be predicted theoretically. The Sanchez-Lacombe theory served as a basis for the description of the solutions at rest. To account for the nonequilibrium condition, the energy stored by the sheared mixtures while flowing was added to the Gibbs energy of mixing. The phase diagrams measured at rest and under atmospheric pressure can well be described by one parameter (Delta epsilon, measuring the interaction energy between unlike mers); Delta epsilon is found to vary linearly with M-0.5. The pressure dependencies of the cloud points (constant M and constant composition) are also modeled appropriately, if Delta epsilon* is allowed to decrease linearly with rising pressure. The predictions concerning the influence of sheer are only qualitatively correct: In accord with the experimental findings, the phase separation conditions are practically identical for the stagnant and for the flowing solutions at low pressures; the homogeneous region is, however, increasingly extended by shear as pressure becomes larger.},
language = {English},
number = {14},
journal = {Macromolecules},
author = {An, L. J. and Wolf, B. A.},
month = jul,
year = {1998},
keywords = {dependence, temperature, diagrams, region},
pages = {4621--4625},
}
@article{maggioni_phase_1998,
title = {Phase diagrams of the system tetrahydrofuran/gamma-butyrolactone poly(ether imide) and determination of interaction parameters},
volume = {39},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000075216800018&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0032-3861(97)10064-7},
abstract = {The thermodynamic interactions in the ternary mixture tetrahydrofuran/gamma-butyrolactone/poly(ether imide) (THF/ gamma-BL/PEI) are investigated from 30 to 50 degrees C. This is a membrane-forming system with a high He-selectivity. Cloud point measurements show that the two binary polymer solutions THF/PEI and gamma-BL/PET exhibit miscibility gaps which close towards the centre of the ternary phase diagram where the mixtures become homogeneous (cosolvency). Vapour pressures were determined for the subsystem THF/gamma-BL. For the theoretical calculations the Gibbs energy of mixing is formulated according to the Flory-Huggins theory and the interaction parameter chi(THF/gamma-BL) calculated from the vapour pressures. The adjustment of theoretical phase diagrams to the experimental data (cloud point curves, tie lines and critical points) gives access to chi(THF/PEI) and chi(gamma-BL/PEI) For a satisfactory representation of the liquid-liquid demixing, a concentration dependent chi(THF/PEI) is required, whereas concentration independent values for chi(THF gamma-BL) and chi(gamma-BL/PEI) suffice. (C) 1998 Elsevier Science Ltd. All rights reserved.},
language = {English},
number = {21},
journal = {Polymer},
author = {Maggioni, J. F. and Nunes, S. P. and Pires, A. T. N. and Eich, A. and Horst, R. and Wolf, B. A.},
month = oct,
year = {1998},
keywords = {flory-huggins parameter, blends, cosolvency, liquid-liquid demixing, ternary mixture},
pages = {5133--5138},
}
@article{stammer_phase_1998,
title = {Phase behaviour and interfacial tension of polysiloxane blends},
volume = {39},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000072456500039&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0032-3861(97)00548-X},
abstract = {The cloud point curve for blends of poly(dimethyisiloxane) (PDMS, M-w = 2.5 kg mol(-1)) and poly(hexyl methylsiloxane) (PHMS, (M-w = 113 kg mol(-1)] was determined turbidimetrically. The system demixes upon cooling and the UCST amounts to 36 degrees C. The interfacial tension gamma was determined at the critical composition for three temperatures by means of a spinning drop tensiometer. The dependence of gamma on the reduced critical temperature can be described within experimental error by both the mean field theory and the Ising-3D theory. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.},
language = {English},
number = {10},
journal = {Polymer},
author = {Stammer, A. and Wolf, B. A.},
month = may,
year = {1998},
keywords = {interfacial tension, polymers, critical region, mixtures, point, poly(dimethylsiloxane), polysiloxane blends},
pages = {2065--2067},
}
@article{stammer_effect_1998,
title = {Effect of random copolymer additives on the interfacial tension between incompatible polymers},
volume = {19},
issn = {1022-1336},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000072350500009&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/(Sici)1521-3927(19980201)19:2<123::Aid-Marc123>3.0.Co;2-J},
abstract = {Interfacial tensions gamma were measured for mixtures of poly(methylphenylsiloxane) (4 kg/mol) and poly(dimethylsiloxane) (24 kg/mol) in the absence and in the presence of small amounts of the random copolymer poly(dimethylsiloxane-ran-methylphenylsiloxane) (89 mol-\% of dimethylsiloxane units, 28 kg/mol) from 25 to 110 degrees C. Approximately 1 wt.-\% of the copolymer additive suffices to reduce gamma from ca. 2.2 to 1.6 mN/m. The time dependence of the apparent gamma value in the course of the attainment of equilibria also indicates surface activity. The hypothesis is formulated that the efficiency of the random copolymer for a reduction of gamma is bound to the condition that it is only sparingly soluble in both blend components.},
language = {English},
number = {2},
journal = {Macromolecular Rapid Communications},
author = {Stammer, A. and Wolf, B. A.},
month = feb,
year = {1998},
keywords = {phase-separation, blends, adhesion, architecture, compatibilizing agents, diblock copolymer, immiscible polymers, profile, ps-pmma copolymer, reinforcement},
pages = {123--126},
}
@incollection{schuld_polymer-solvent_1999,
address = {New York},
edition = {4th},
title = {Polymer-{Solvent} {Interaction} {Parameters}},
abstract = {The classical thermodynamics of binary polymer-solvent systems was developed independently by P.J. Flory and M. L. Huggins. It is based on the well-known lattice model qualitatively formulated by K. H. Meyer, who pointed out the effect of the differences in molecular size of polymer and solvent molecules on the entropy of mixing. The quantitative calculation of the entropy of mixing led to the introduction of a dimensionless quantity, the so-called Flory-Huggins interaction parameter c, for the thermodynamic description of polymer solutions. It was evident from the beginning that c is a function of T, however at first c was considered to be independent of the concentration of the polymer. Subsequent experiments have shown the necessity to treat c as a function of composition. Furthermore c also depends on M2 (the molecular weight of the polymer), not only at high dilution, but - according to recent experiments - even in the range of large polymer concentration.},
booktitle = {Polymer {Handbook}},
publisher = {John Wiley \& Sons},
author = {Schuld, Norbert and Wolf, B. A.},
editor = {Brandrup, J. and Immergut, E. H. and Grulke, E. A.},
year = {1999},
}
@article{wolf_interfacial_1999,
title = {Interfacial tension between polymer-containing liquids - {Predictability} and influences of additives},
volume = {139},
issn = {1022-1360},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000081388900009&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/masy.19991390110},
abstract = {The first part of the contribution deals with the interfacial tension, sigma, of phase-separated polymer solutions in single or mixed solvents and of binary polymer blends as a function of the relative distance to the critical temperature of the system, special attention being paid to the possibilities of theoretical prediction. Two methods are discussed in more detail. One is based on a realistic description of the Gibbs energy of mixing as a function of composition, the second correlates sigma with the length of the measured tie line. The second part is devoted to another aspect, namely the effects of additives on the interfacial tension between the coexisting phases of demixed polymer solutions and between highly incompatible polymers. In the former case, it is demonstrated that an addition of a thermodynamically good solvent is normally associated with a reduction in sigma; however, adding a high-molecular-weight compound which is incompatible with the dissolved polymer leads to an increase in sigma. The interfacial tension between incompatible homopolymers is efficiently reduced by block copolymers consisting of monomeric units which are either identical with or different from those of the homopolymers; in contrast to theoretical expectation, the molecular architecture of the additives seems to be of minor importance only. Random copolymers which are insoluble in the homopolymers can also efficiently reduce the interfacial tension.},
language = {English},
journal = {Macromolecular Symposia},
author = {Wolf, B. A.},
month = apr,
year = {1999},
pages = {87--92},
}
@article{horst_phase_1998,
title = {Phase diagrams calculated for flowing polymer solutions: spinodal and three phase conditions},
volume = {40},
issn = {0170-0839},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000072407900031&action=retrieve&mode=FullRecord},
doi = {DOI 10.1007/s002890050262},
abstract = {Spinodal lines and critical points (CPs) are calculated for flowing solutions of polystyrene in trans-decalin. Three types of CPs can be distinguished: The first consists of stable CPs (ordinary critical line) and originates from the CP of the quiescent system. The other two CPs are bound to shear. Additional stable CPs (extraordinary critical line) result for higher polymer concentrations and unstable CPs for intermediate concentrations. Ordinary and unstable critical line merge in a heterogeneous double CP. The coexistence of three phases in the flowing system (eulytic points) comes to an end as two of them merge upon an increase in shear rate at a critical end point.},
language = {English},
number = {2-3},
journal = {Polymer Bulletin},
author = {Horst, R. and Wolf, B. A.},
month = mar,
year = {1998},
keywords = {shear, blends, 2 homopolymers, corresponding copolymer, derivatives, mixture, separation},
pages = {353--360},
}
@article{wolf_shear_1999,
title = {Shear influences on the phase separation of blends made of homopolymer {A} and random copolymer {A}-{B}},
volume = {110},
issn = {0021-9606},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000079625600050&action=retrieve&mode=FullRecord},
doi = {Doi 10.1063/1.478657},
abstract = {Shear induced changes in the demixing conditions are discussed for the copolymer blends of the present type in terms of a distortion of quasichemical equilibria established in the stagnant systems between the two different kinds of polymer segments. Calculations were performed in an attempt to rationalize experimental results obtained with blends exhibiting upper critical solution temperatures. The proposed model accounts for the experience that the first observable effect of shear consists of an enlargement of the two-phase regime (a behavior which differs fundamentally from that of homopolymer blends or homopolymer solutions) and yields the correct order of magnitude for the effects. The influences of copolymer composition, number of segments of the components, and temperature dependence of the Flory-Huggins interaction parameter are discussed in detail. Furthermore, it is demonstrated how the present considerations relate to an earlier approach based on the energy a system can store while it flows. (C) 1999 American Institute of Physics. [S0021-9606(99)50115-3].},
language = {English},
number = {15},
journal = {Journal of Chemical Physics},
author = {Wolf, B. A.},
month = apr,
year = {1999},
keywords = {flow, behavior, miscibility, polymer blends, derivatives, poly(2,6-dimethyl-1,4-phenylene oxide)},
pages = {7542--7547},
}
@article{stohr_continuous_1998,
title = {Continuous polymer fractionation of polysaccharides using highly substituted trimethylsilylcellulose},
volume = {199},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000075869600018&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.1998.021990918},
abstract = {Trimethylsilylcellulose (TMSC) was prepared from commercial cellulose with a mixture of hexamethyldisilazane and chlorotrimethylsilane in the solvent system N,N-dimethylacetamide/lithium chloride. The soluble, highly silylated polymer (degree of substitution, DS 2.9) had a molar mass (M) over bar(w) of 500 kg/mol and a molecular non-uniformity U = ((M) over bar(w)/(M) over bar(n)) - 1 of 2.9. In order to investigate the principal suitability of a continuous polymer fractionation for polysaccharides like cellulose derivatives and to obtain TMSC with different molecular weights and lower non-uniformity TMSC was fractionated by means of CPF (Continuous Polymer Fractionation), well-established in the field of synthetic polymers. The samples were fractionated using a mixed solvent, composed of toluene and dimethyl sulfoxide, and characterized by capillary viscometry, gel permeation chromatography (GPC), and GPC-light scattering coupling. The molar masses of the fractions range from 110 to 600 kg/mol and their U values vary between 0.9 and 1.9. The intrinsic viscosities of TMSC in tetrahydrofuran at 25 degrees C and (M) over bar(w) are related by [eta] = K . M-w(a), where K = 0.0089 mL/g and a = 0.82.},
language = {English},
number = {9},
journal = {Macromolecular Chemistry and Physics},
author = {Stohr, T. and Petzold, K. and Wolf, B. A. and Klemm, D. O.},
month = sep,
year = {1998},
keywords = {cellulose},
pages = {1895--1900},
}
@article{horst_shear_1998,
title = {Shear influences on the solubility of {LDPE} in ethene},
volume = {14},
issn = {0896-8446},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000077142600006&action=retrieve&mode=FullRecord},
doi = {10.1016/s0896-8446(98)00105-3},
abstract = {The influence of shear on the demixing pressures of the binary system ethene/polyethene was determined viscometrically in the temperature range 147-195 degrees C up to pressures of 1400 bar at polymer concentrations of 18.4, 22.5 and 27.4 wt\%, respectively. Autoclaves were used to prepare the solutions and to measure cloud points for the stagnant system. A high-pressure viscometer was used to perform experiments at shear rates gamma up to 1500 s(-1). Under all conditions investigated here the two-phase area grows as gamma becomes larger and the demixing pressures increase up to 23 bar. This observation is in contrast to theoretical expectation according to which it should be the one-phase region which expands under the prevailing conditions. (C) 1998 Elsevier Science B.V. All rights reserved.},
language = {English},
number = {1},
journal = {Journal of Supercritical Fluids},
author = {Horst, R. and Wolf, B. A. and Kinzl, M. and Luft, G. and Folie, B.},
month = oct,
year = {1998},
keywords = {phase-separation, behavior, shear, phase separation, blends, mixtures, copolymers, ethylene, flow-induced demixing, flowing polymer-solutions, influences, polyethylene (LDPE), supercritical ethene},
pages = {49--54},
}
@article{kinzl_viscosity_2003,
title = {Viscosity of solutions of low-density polyethylene in ethylene as a function of temperature and pressure},
volume = {47},
issn = {0148-6055},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000183986900004&action=retrieve&mode=FullRecord},
doi = {Doi 10.1122/1.15266036},
abstract = {The viscosity, eta, of solutions of low-density polyethylene (M-w = 162 kg/mol) in ethylene containing 18.4, 22.5, 27.4, and 35.0 wt \% polymer, respectively, was measured over a wide range of temperatures, pressures, and shear rates. The equipment used consisted of a high-pressure autoclave in which the solutions were prepared and a rotational viscometer which was operated by a computer. The solution with a polymer concentration of 35 wt \% was found to be shear thinning. Due to experimental inaccuracy the shear influence on the viscosity of the mixtures with lower polymer content could not be identified clearly. The zero-shear viscosities show the expected increase of 77 according to the pressure or polymer concentration and a corresponding reduction of 17 as the temperature is increased. The results are consistent with current theories and can be described well by a mathematical expression based on activation energies, and activation volumes, and on exponential growth of eta with a rise in polymer concentration. (C) 2003 The Society of Rheology.},
language = {English},
number = {4},
journal = {Journal of Rheology},
author = {Kinzl, M. and Luft, G. and Horst, R. and Wolf, B. A.},
month = aug,
year = {2003},
keywords = {dependence, behavior, mixtures, 200 mpa, ethene, liquid hydrocarbons, range 298-453-k},
pages = {869--877},
}
@incollection{higgins_polymer-containing_1999,
address = {Oxford},
title = {Polymer-{Containing} {Mixtures} in {Flow}},
booktitle = {Chemical {Thermodynamics} for the 21 {Century}},
publisher = {Blackwell Science Ltd},
author = {Higgins, Julia S. and Horst, Roland and Wolf, Bernhard Anton},
editor = {Letcher, T. M.},
year = {1999},
pages = {209--216},
}
@article{reisinger_influence_1998,
title = {Influence of chain length on the molecular dynamics of an aliphatic ionene},
volume = {49},
issn = {0323-7648},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000077810500006&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/(Sici)1521-4044(199812)49:12<710::Aid-Apol710>3.0.Co;2-8},
abstract = {An aliphatic random copolymer ionene (a cationic polyelectrolyte with N+ in the repeat unit), was fractionated with the continuous polymer fractionation and investigated for its molecular weight dependent properties. The fractions were analyzed with GPC and capillary viscometry for their molecular weight. Glass transition temperatures were determined with DSC and a strong molecular weight dependence was observed, but no influence in the ionic conductivity was observed. The temperature dependency of ionic conductivity in ionenes is described.},
language = {English},
number = {12},
journal = {Acta Polymerica},
author = {Reisinger, T. and Meyer, W. H. and Wegner, G. and Haase, T. and Schultes, K. and Wolf, B. A.},
month = dec,
year = {1998},
keywords = {continuous fractionation, dependence, polyelectrolytes, glass-transition},
pages = {710--714},
}
@article{ziegler_viscosity_1999,
title = {Viscosity and morphology of the two-phase system {PDMS}/{P}({DMS}-ran-{MPS})},
volume = {43},
issn = {0148-6055},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000081345600012&action=retrieve&mode=FullRecord},
doi = {Doi 10.1122/1.551011},
abstract = {Stationary state viscosities eta were measured at 50 degrees C for two-phase blends consisting of poly(dimethylsiloxane) (PDMS) and poly(dimethylsiloxane-ran-methylphenyl-siloxane) (COP) at different compositions as a function of shear rate up to 100 s(-1). All mixtures exhibit shear-thinning behavior in contrast to the pure components; the sensitivity of eta towards shear varies with the composition in a characteristic manner reflecting the morphology of the blends. On the basis of these rheological results we infer that the concept of a single composition of co-continuity should be replaced by a composition range of co-continuity. For blends consisting of droplets of one phase suspended in the matrix of the complementary phase pictures were taken after rapid transfer from the shear cell (100 s(-1)) into the light microscope. The average dimensions of the droplets are approximately 13 mu m (PDMS matrix) and 14 mu m (COP matrix); this observation is in contrast with the data calculated according to Wu [Wu, S., "Formation of dispersed phase in incompatible polymer blends: Interfacial and rheological effects," Polym. Eng. Sci. 27, 335-343 (1987)] from the interfacial tension, which we have measured as a function of temperature, and from the viscosity ratios of the two phases. For the PDMS matrix this prediction (24 mu m) is reasonable; however, if the matrix consists of COP, the theoretical result exceeds the measured dimension by approximately a factor of 14. Micrographs of a blend containing 60 vol\% PDMS taken in situ at 1 s(-1) under stationary conditions disclose thread-like structures. The correlation between the prevalence of certain morphologies and the extent of shear thinning is discussed. (C) 1999 The Society of Rheology. [S0148-6055(99)01204-3].},
language = {English},
number = {4},
journal = {Journal of Rheology},
author = {Ziegler, V. and Wolf, B. A.},
month = aug,
year = {1999},
keywords = {shear-flow, interfacial-tension, immiscible polymer blends, coalescence, emulsions, inversion, melt, model, rheological properties, viscoelastic liquids},
pages = {1033--1045},
}
@article{schnell_molecular_1999,
title = {Molecular surfaces: {An} advantageous starting point for the description of composition-dependent viscosities applied to polymer solutions},
volume = {37},
issn = {0887-6266},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000081721700024&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/(Sici)1099-0488(19990815)37:16<2221::Aid-Polb24>3.0.Co;2-2},
abstract = {The viscosity of polymer/solvent systems is modeled as a function of composition under the premises that the dissipation of energy is taking place at the molecular interfaces and that the friction between solvent and solute varies with composition due to a change in the flow mechanism (drainage of coils). The simple expression obtained in this manner contains three system-specific parameters: a geometric factor gamma, which accounts for the differences of the surface to volume ratios of the components; a hydrodynamic parameter alpha, which measures the friction between solute and solvent in the case of fully draining polymer coils; and beta, which corrects for changes in the friction between unlike molecules resulting from collective motions owing to limited draining. Experimental data published for 12 poly(dimethylsiloxane)/pentamer mixtures can be represented quantitatively by this relation; moreover the knowledge of the three system-specific parameters permits the calculation of intrinsic viscosities, and the molecular weight dependencies of gamma and alpha yield the entangle molecular weight of the polymer. (C) 1999 John Wiley \& Sons, Inc.},
language = {English},
number = {16},
journal = {Journal of Polymer Science Part B-Polymer Physics},
author = {Schnell, M. and Wolf, B. A.},
month = aug,
year = {1999},
keywords = {polymer solutions, viscosity, poly(dimethylsiloxane), excess viscosities, molecular surfaces, polymer mixtures, surface fractions},
pages = {2221--2228},
}
@article{hinrichs_blends_1999,
title = {Blends of {PDMS} and random copolymers of dimethylsiloxane and methylphenylsiloxane: {Phase} separation in the quiescent state and under shear},
volume = {200},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000078609100009&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/(Sici)1521-3935(19990201)200:2<368::Aid-Macp368>3.0.Co;2-R},
abstract = {The miscibility of random copolymers (COP), consisting of dimethylsiloxane and methylphenylsiloxane units, with poly(dimethylsiloxane)s (PDMS) was studied in the absence and in the presence of shear experimentally as well as theoretically. Blends of COP0.86 28 with PDMS 33 (subscripts: volume fraction of DMS in the copolymer, numbers after thc abbreviations: weight average molar masses in kg/mol) were investigated far from critical conditions on the PDMS side of the phase diagram. According to these experiments the two phase regime increases by shear without exception and the maximum effects: grow from 3 to 12 K as the PDMS concentration increases. Theoretical calculations were performed under the: premise that shear destroys clusters of like segments formed under equilibrium conditions, The effects ts calculated in this manner are of the comet order of magnitude, but their concentration dependence contradicts the measurements. Blends of COP0.71 7 With PDMS 27, PDMS 33, or PDMS 38 exhibit critical concentrations at approx. 23 wt.-\% PDMS. For sufficiently low PDMS contents shear reduce's the miscibility again according to experiment and theory. However, measurements demonstrate that the susceptibility of the blends towards shear decreases as the concentration of PDMS increases until the effect changes sign and the homogeneous region expands as the systems flow, in contrast to the calculations which yield a monotonous increase of shear effects. Possible reasons for the observed discrepancies an discussed.},
language = {English},
number = {2},
journal = {Macromolecular Chemistry and Physics},
author = {Hinrichs, A. and Wolf, B. A.},
month = feb,
year = {1999},
keywords = {polystyrene, behavior, diagrams, derivatives, common solvent, dynamics, highly incompatible polymers},
pages = {368--375},
}
@article{barth_quick_2000,
title = {Quick and reliable routes to phase diagrams for polyethersulfone and polysulfone membrane formation},
volume = {201},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000085403600012&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/(Sici)1521-3935(20000201)201:3<365::Aid-Macp365>3.0.Co;2-5},
abstract = {Phase diagrams were measured and calculated for the ternary membrane forming systems DMF/water/polysulfone and DMF/water/polyethersulfone at different temperatures. Customary experiments yielded cloud point curves, tie lines, and critical compositions. The theoretical computation starts from the Flory-Huggins theory and employs binary interaction parameters g(ij) that vary with the composition. This information was mainly obtained by means of Headspace-Gas Chromatography (HSGC, yielding the partial pressures of the volatile components); these data were complemented by light scattering and swelling experiments. The calculation of binodals, spinodals, tie lines, and critical points avoids the elaborate use of chemical potentials and minimizes the Gibbs energy directly. In order to reach total agreement between measured and calculated ternary phase diagrams it is necessary to adjust the interaction parameter between the polymers and water. Discrepancies between the values obtained in this way and the values resulting from measurements with the binary subsystems indicate the necessity of ternary interaction parameters g(ijk).},
language = {English},
number = {3},
journal = {Macromolecular Chemistry and Physics},
author = {Barth, C. and Wolf, B. A.},
month = feb,
year = {2000},
keywords = {behavior, polymer, systems, solvent, mixtures, derivatives, separation, energy, nonsolvent, water},
pages = {365--374},
}
@article{badiger_interrelation_2000,
title = {Interrelation between the thermodynamic and viscometric behaviour of aqueous solutions of hydrophobically modified ethyl hydroxyethyl cellulose},
volume = {41},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000083929000016&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0032-3861(99)00294-3},
abstract = {Aqueous solutions of a commercial sample of hydrophobically modified ethyl hydroxyethyl cellulose (HC, M-w = 100 kg/mol, nonylphenol substitution ca. 1.7 mol\%) were studied with respect to their demixing behaviour and flow characteristics. Phase separation temperatures were measured turbidimetrically and by determining the first discernible macroscopic phase separation. In some cases demixing was also monitored viscometrically. Phase volume ratios yielded a critical polymer concentration of 1.87 wt.\% HC (displaced considerably our of the minimum of the demixing curve towards higher polymer concentrations) and a lower critical solution temperature of 47 degrees C. Model calculations of the spinodal curve indicate a moderately exothermal heat of mixing. This conclusion is backed by the intrinsic viscosities determined from 25 to 55 degrees C. In this T-range [eta] falls in a sigmoidal manner to approximately one forth of its value at the lowest temperature (430 ml/g). In spite of short, stiff chains and high dilution (max. 2.5 wt.\% HC) these liquids have a highly developed tendency of shear thinning. Further, they exhibit an uncommonly large critical excess viscosity and the dependencies of the zero shear viscosities on composition and temperature show several peculiarities. All these findings and the observed shear induced expansion of the homogenous region by more than 5 degrees C are explained consistently in terms of long-lived clusters between the hydrophobic entities of HC established under equilibrium conditions. (C) 1999 Elsevier Science Ltd. All rights reserved.},
language = {English},
number = {4},
journal = {Polymer},
author = {Badiger, M. V. and Lutz, A. and Wolf, B. A.},
month = feb,
year = {2000},
keywords = {polymer-solutions, shear, phase-diagrams, copolymers, aqueous solutions, hydrophobically modified ethyl hydroxyethyl cellulose, phase diagram},
pages = {1377--1384},
}
@article{schneider_specific_2000,
title = {Specific features of the interfacial tension in the case of phase separated solutions of random copolymers},
volume = {41},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000085565200021&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0032-3861(99)00643-6},
abstract = {Phase diagrams (cloud point curves, critical points, tie lines for constant critical composition) and interfacial tensions as a function of temperature were measured for solutions of two random copolymers: poly(dimethylsiloxane-ran-methylphenylsiloxane) [I] and poly(sty rene-ran-acrylonitrile) [II]. Acetone and anisole served as solvents for I and toluene for II; all solutions exhibit UCSTs between 300 and 310 K. The phase separation behavior can be well modeled if one accounts for the molecular and chemical non-uniformities of the random copolymers used in this study. The interfacial tensions sigma differ most markedly from that of comparable homopolymer solutions in their correlation sigma = sigma(tau)tau(mu), where tau = (T-c - T)/T-c. For all three systems sigma(tau) results considerably less and the critical exponent mu varies widely from 0.68 to 2.18 (in contrast to the normal case where mu is on the order of 1.3-1.5). Both observations are explained in terms of the capability of copolymers to minimize the interfacial energy by suitably arranging their different monomeric units. Model calculations were performed in terms of the energy required to transfer molecules from one phase to the other, assembling the average polymer-solvent interaction parameter from the three binary interaction parameters g(ij), required to describe copolymer solutions. These results demonstrate that the experimentally observed particularities of copolymers are more Likely dominated by dissimilarities in the concentration dependence of g(ij) than by unlike temperature dependencies. Particularities in the correlations of the length of the tie line with tau and sigma, respectively, are also discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.},
language = {English},
number = {11},
journal = {Polymer},
author = {Schneider, A. and Wolf, B. A.},
month = may,
year = {2000},
keywords = {interfacial tension, behavior, polymers, phase diagrams, random copolymer solutions},
pages = {4089--4097},
}
@article{horst_computation_1998,
title = {Computation of {Unstable} {Binodals} {Not} {Requiring} {Concentration} {Derivatives} of the {Gibbs} {Energy}},
volume = {102},
issn = {1089-5647},
abstract = {The equilibrium of three liquid phases in a binary mixture implies the existence of tie lines and binodals that are different from the normal experimentally observable ones. First of all, there are the metastable extensions of the binodal built up by S/S tie lines. These S/S tie lines fulfill the equilibrium condition of the minimum of the Gibbs energy of the entire two-phase system. Both coexisting phases are located within the meta(stable) region, There are two additional types of tie lines: U/U (maximum of the Gibbs energy; both end points within the unstable area) and U/S tie lines (saddle point; one end point within the (meta)stable, the other within the unstable region). All types of tie lines fulfill the condition that the chemical potentials of each component have to be equal in the two phases given by the end points of the tie line. It is shown how all these tie lines build up the binodal and which rules they have to obey. A method for the calculation of all types of tie lines is presented that requires only the knowledge of the Gibbs energy of mixing; there is no need to calculate the chemical potentials. The method is applied to a Sanchez-Lacombe lattice fluid, and a polymer solution described by an extended Flory-Huggins model accounting for nonpolar and polar interactions.},
number = {17},
journal = {Journal of Physical Chemistry B},
author = {Horst, Roland},
month = apr,
year = {1998},
keywords = {Homopolymers-, Model-, Phase-Diagrams},
pages = {3243--3248},
}
@incollection{wolf_flow_2000,
address = {Dordrecht, Boston, London},
series = {{NATO} {Science} {Series}},
title = {Flow induced mixing and demixing in polymer blends},
volume = {E-370},
abstract = {The observation that the phase separation of flowing polymer containing liquids needs not be identical with their equilibrium behavior dates back almost half a century. The interest in these phenomena remained vivid over the years, but lately they have also gained great practical relevance because of the increasing industrial interest in multiphase systems for the purpose of blending known polymers to produce materials with improved properties. Several experimental techniques may be used to detect the demixing of systems in the quiescent state and in the presence of mechanical fields. The simplest method consists in the determination of cloud points by means of the naked eye. If the viscosities of the constituents of the mixture differ sufficiently, rheological means provide another convenient tool. In principle, any physico-chemical property showing a suitable concentration dependence can be used.},
number = {E},
booktitle = {Structure {Development} in {Processing} for {Polymer} {Property} {Enhancement}},
publisher = {Kluwer academic publishers b.v.},
author = {Wolf, B. A.},
editor = {Cunha, A. M. and Fakirov, S.},
year = {2000},
pages = {295--310},
}
@article{an_shear_2000,
title = {Shear induced mixing/demixing: {Blends} of homopolymers, of homopolymers plus copolymers, and blends in solution},
volume = {149},
issn = {1022-1360},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000086672700012&action=retrieve&mode=FullRecord},
doi = {10.1002/1521-3900(200001)149:1<75::aid-masy75>3.0.co;2-o},
abstract = {Shear may shift the phase boundary towards the homogeneous state (shear induced mixing, SIM), or in the opposite direction (shear induced demixing, SID). SIM is the typical behavior of mixtures of components of low molar mass and polymer solutions, SID can be observed with solutions of high molar mass polymers and polymer blends at higher shear rates. The typical sequence with increasing shear rate is SIM, then occurrence of an isolated additional immiscible area (SLD), melting of this island into the main miscibility gap, and finally SIM again. A three phase line originates and ends in two critical end points. Raising pressure increases the shear effects. For copolymer containing systems SID is sometimes observed at very low shear rates, preceding the just mentioned sequence of shear influences.},
language = {English},
journal = {Macromolecular Symposia},
author = {An, L. and Hinrichs, A. and Horst, R. and Krause, C. and Wolf, B. A.},
month = jan,
year = {2000},
keywords = {phase-separation, behavior, diagrams, flowing polymer-solutions, miscibility gaps},
pages = {75--79},
}
@article{higgins_shear_2000,
title = {Shear influences of polymer blends: experimental, theoretical approaches and technical implications},
volume = {149},
abstract = {We examine the effects of shear on polymer blends consisting of partially miscible components, i.e. systems close to the phase boundary. The eminent phenomenon is the shift of the phase boundary, either extending the homogeneous area (flow-induced mixing) or the opposite effect (flow-induced demixing). The kinetics of the demixing process and concentration fluctuations are also influenced by flow fields, inducing anisotropy due to the flow direction. Experiments (scattering, rheology, in-situ flow-scattering, microscopy, DSC) are carried out with the academic model blend polystyrene/poly(vinyl methyl ether) and the industrial poly(styrene-co-maleic anhydride)/poly (methyl methacrylate) blend. The experimental results are rationalised in terms of a generalised Gibbs energy of mixing by including the energy which is stored in the sheared fluids.},
journal = {Macromolecular Symposia},
author = {Higgins, Julia S. and Hervet, Gerard and Vlassopoulos, Dimitris and Horst, Roland and Wolf, Bernhard Anton},
year = {2000},
pages = {165--170},
}
@article{maggioni_viscosity_2000,
title = {On the viscosity of moderately concentrated solutions of poly(ether imide) in a mixed solvent of marginal quality},
volume = {41},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000086228500044&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0032-3861(99)00819-8},
abstract = {Viscosities eta were measured for moderately concentrated (15.5 wt\%) solutions of poly(ether imide) (PEI) as a function of the composition of the cosolvent tetrahydrofuran (THF) plus gamma-butyrolactone (gamma-BL). The solutions are almost by a factor of four less viscous when THF predominates than when gamma-BL, is the major component of the solvent mixture. Furthermore, the viscosity passes a minimum as the composition of the mixed solvent is varied. Both observations can be well understood in terms of the viscosities of the mixed solvents and the hydrodynamic interaction between the polymer molecules. The pronounced dissymmetry of eta as a function of the composition of the mixed solvent eta results from the fact that the viscosity of gamma-BL is three times larger than that of THF. The minimum in eta reflects the dependence of the thermodynamic quality of the mixed solvent on its composition. With increasing predominance of one component the solvent deteriorates and additional polymer/polymer contacts-leading to an augmentation of eta-are formed. (C) 2000 Elsevier Science Ltd. All rights reserved.},
language = {English},
number = {12},
journal = {Polymer},
author = {Maggioni, J. F. and Eich, A. and Wolf, B. A. and Nunes, S. P.},
month = jun,
year = {2000},
keywords = {continuous fractionation, polystyrene, polymer-solutions, viscosity, cosolvency, poly(ether imide), pressure-dependence, pvc},
pages = {4743--4746},
}
@article{barth_asymmetric_2000,
title = {Asymmetric polysulfone and polyethersulfone membranes: effects of thermodynamic conditions during formation on their performance},
volume = {169},
issn = {0376-7388},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000086199200012&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0376-7388(99)00344-0},
abstract = {Membranes of polysulfone (PSU) and polyethersulfone (PES) were prepared from ternary and quaternary mixtures containing N,N-dimethylformamide (DMF) as solvent, water as non-solvent, and acetone (AC) as additive. The conditions for phase inversion and the desired phase separation mechanisms were selected on the basis of the phase behavior determined for the solvent/non-solvent/polymer systems. The influences of the composition of the casting solution, of the support, and of film thickness on structure and permeation properties of the membranes were analyzed by scanning electron microscopy (SEM) plus flux and separation experiments. The mechanisms of phase inversion that should prevail under the different conditions according to the measured phase diagrams were corroborated by means of light scattering experiments. (C) 2000 Elsevier Science B.V. All rights reserved.},
language = {English},
number = {2},
journal = {Journal of Membrane Science},
author = {Barth, C. and Goncalves, M. C. and Pires, A. T. N. and Roeder, J. and Wolf, B. A.},
month = may,
year = {2000},
keywords = {phase-separation, nonsolvent, nucleation and growth, phase inversion membranes, polyethersulfone, polysulfone, spinodal decomposition},
pages = {287--299},
}
@article{schnell_viscosity_2000,
title = {Viscosity of polymer/solvent systems: {Quantitative} description on the basis of molecular surfaces},
volume = {44},
issn = {0148-6055},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000086966000010&action=retrieve&mode=FullRecord},
doi = {Doi 10.1122/1.551103},
abstract = {A model for the description of the viscosity of polymer/solvent systems made up of homologues, developed earlier, is generalized to normal polymer solvent mixtures. It is based on three premises: (i) the dissipation of energy takes place at the molecular interfaces; (ii) the friction between solvent and solute varies with composition due to a change in the flow mechanism (drainage of coils); and (iii) the specific coil volume generally also depends on polymer concentration. The resulting simple expression contains four system-specific parameters: a geometric factor gamma, which accounts for the differences of the surface to volume ratios of the components; a viscometric interaction parameter a, which measures the friction between solute and solvent in the case of fully draining polymer coils; [eta], the specific hydrodynamic volume of the polymer at infinite dilution (intrinsic viscosity), and eta the specific hydrodynamic volume under Theta conditions. The suitability of this model is demonstrated by means of extensive experimental data reported in the literature for the systems diethyl phthalate/poly(vinyl acetate) and diethyl phthalate/poly(methyl acrylate). It appears worthwhile to mention that the evaluation yields [eta] and eta, even in the absence of information within the relevant composition range, and that there exists a linear correlation between gamma and alpha. (C) 2000 The Society of Rheology. [S0148-6055(00)00503-9].},
language = {English},
number = {3},
journal = {Journal of Rheology},
author = {Schnell, M. and Wolf, B. A.},
month = jun,
year = {2000},
keywords = {polymer-solutions},
pages = {617--628},
}
@article{loske_fractionation_2000,
title = {Fractionation of unsubstituted cellulose from solutions in either {Ni}-tren or ({N},{N}-dimethylacetamide plus {LiCl})},
volume = {201},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000165339800005&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/1521-3935(20001001)201:15<1940::Aid-Macp1940>3.0.Co;2-5},
abstract = {Starting from solutions of unsubstituted cellulose (Avicel PH101, (M) over bar (w) = 30.1 kg/mol and (M) over bar (w)/(M) over bar (n) = 3 or Solucell 500, (M) over bar (w) = 230 kg/mol, (M) over bar (w)/(M) over bar (n) = 2.8) in either Ni-tren (0.8 M aqueous solution of the dihydroxotris(2-aminoethly)amine nickel(II) complex) or in a mixed solvent DMAc+LiCl (consisting of N,N-dimethylacetamide plus lithium chloride) it was investigated whether the segregation of a second phase caused by the addition of suitable precipitants leads to polymer fractionation. With Ni-tren the long chains accumulate in the precipitate formed upon the addition of sulfuric acid; as the pH falls below approximate to9, the solution is free of cellulose. Nevertheless this route option for fractionation must be ruled out because of a pronounced chain scission taking place in that solvent. For (DMAc+LiCl) the best low molecular weight precipitant that could be found was acetone; it allows the fractionation of the lower molecular weight Avicel but fails for Solucell as a result of the high viscosities of its solutions in the presence of acetone. It was therefore investigated whether that deficiency could be overcome by the use of high molecular precipitants. In these experiments poly(methyl methacrylate), incompatible with cellulose, was used to cause phase separation. The results demonstrate the suitability of this system for discontinuous experiments even in the case of the higher molecular weight Solucell.},
language = {English},
number = {15},
journal = {Macromolecular Chemistry and Physics},
author = {Loske, S. and Lutz, A. and Striouk, S. and Wolf, B. A.},
month = oct,
year = {2000},
keywords = {continuous polymer fractionation, solvents},
pages = {1940--1945},
}
@article{striouk_fractional_2000,
title = {Fractional dissolution of "solid" unsubstituted cellulose},
volume = {201},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000165339800006&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/1521-3935(20001001)201:15<1946::Aid-Macp1946>3.0.Co;2-6},
abstract = {Activated cellulose (Solucell, DPw = 1400) was extracted stepwise at room temperatures by means of mixed solvents consisting of N,N-dimethylacetamide (DMAc) and LiCl, starting with a salt concentration of 1 wt-\% and increasing it in increments of 1 wt.-\% up to 7 wt.-\%. Upon the regeneration of the thus obtained cellulose fractions by pouring the solutions dropwise into a large surplus of water, part of the mixed solvent is occluded in the polymer. For that reason the cellulose samples were purified by redissolving them in Ni-tren and by a second precipitation. This process, however, leads to pronounced polymer degradation. For that reason we have used a spinning nozzle to press the extracts in a highly dispersed form into water. Using this procedure the samples were Ilo longer contaminated by inclusions. The intrinsic viscosities of the fractions (in an alkaline aqueous solution of ferric tartaric acid complex at 25 degreesC) and their GPC diagrams (solvent DMAc + LiCl) demonstrate that the shortest chains ([eta] = 208 mL/g) become soluble first and the longest chains ([eta] = 680 mL/g) last. The present data lead to the following Kuhn-Mark-Houwink relation [eta] = 4.13 DPw0.68. The current results indicate a promising route to obtain larger quantities of unsubstituted cellulose with narrow molecular weight distribution by means of suitable extraction strategies.},
language = {English},
number = {15},
journal = {Macromolecular Chemistry and Physics},
author = {Striouk, S. and Wolf, B. A.},
month = oct,
year = {2000},
pages = {1946--1949},
}
@article{barth_preferential_2000,
title = {Preferential evaporation of precipitants from polymer solutions in mixed solvents},
volume = {21},
issn = {1022-1336},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000087142700003&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/(Sici)1521-3927(20000401)21:7<349::Aid-Marc349>3.0.Co;2-W},
abstract = {Partial vapor pressures were measured for the volatiles of solutions of polysulfone or polyethersulfone in mixtures of N,N-dimethylformamide (DMF, solvent) and water or acetone (precipitants) by means of headspace gas chromatography. The results demonstrate that the enrichment of water in the gas phase increases exponentially with rising polymer concentration, in contrast to that of acetone which remains constant. The reinforced expulsion of water resulting from the presence of polymers is theoretically conceivable and should be useful in the field of separation techniques.},
language = {English},
number = {7},
journal = {Macromolecular Rapid Communications},
author = {Barth, C. and Wolf, B. A.},
month = may,
year = {2000},
keywords = {headspace gas-chromatography, liquid equilibria, parameters},
pages = {349--353},
}
@article{eich_electro-_2000,
title = {Electro- and magneto-rheology of nematic liquid crystals: {Experiment} and nonequilibrium molecular dynamics computer simulation},
volume = {113},
issn = {0021-9606},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000088878400042&action=retrieve&mode=FullRecord},
doi = {Pii [S0021-9606(00)71433-4] Doi 10.1063/1.1287851},
abstract = {The viscosity of the nematic liquid crystal PCH-5 [4-(trans-4'-pentylcyclohexyl)-benzonitrile], measured in the presence of an electric field parallel to the gradient of the velocity, shows a complex dependence both on magnitude E of the electric field and on the shear rate (gamma) over dot. When plotted versus E(2)/(gamma) over dot, all data points fall unto a master curve. In nonequilibrium molecular dynamics computer simulations, performed for a Gay-Berne model fluid, the corresponding influence of a magnetic field on the viscosity was calculated. In both cases, the shape of the master curve for the viscosity can be computed by considering the competition between the torques exerted by the velocity gradient and by the orienting field. It involves the Leslie viscosity coefficients gamma(1) and gamma(2), the Miesowicz and Helfrich viscosities eta(1),eta(2), and eta(12). Thus it should be possible to extract these coefficients from the data. This is straightforward in the magnetic case since the molecules in the fluid "see" the externally applied field. The internal electric field, however, differs from the applied field E. When this effect is taken into account, using the known experimental values for dielectric coefficients epsilon(parallel to) and epsilon(perpendicular to), the electro-rheological master curve agrees very well with the experimental data. Values for the viscosity coefficients are obtained and presented. (C) 2000 American Institute of Physics. [S0021-9606(00)71433-4].},
language = {English},
number = {9},
journal = {Journal of Chemical Physics},
author = {Eich, A. and Wolf, B. A. and Bennett, L. and Hess, S.},
month = sep,
year = {2000},
keywords = {behavior, affine transformation model, dense fluids, equilibrium, flow-alignment, gay-berne model, induced structural-changes, shear-induced anisotropy, spherical-particles, viscosity coefficients},
pages = {3829--3838},
}
@article{barth_evidence_2000,
title = {Evidence of ternary interaction parameters for polymer solutions in mixed solvents from headspace-gas chromatography},
volume = {41},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000088612000014&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0032-3861(00)00261-5},
abstract = {Partial vapor pressures of the volatiles have been measured for four solvent/precipitant/polymer systems at different temperatures. The high molecular weight compounds were polysulfone or polyethersulfone and the mixed solvent was either DMF/acetone or DMF/water. Systems containing the very powerful precipitant water exhibit a special phenomenon: Upon the addition of polymer to a mixed solvent of constant composition the partial vapor pressure of water increases by a factor of more than two before it falls to zero as the volume fraction of the polymer approaches unity. This particular situation cannot be modeled using binary interaction parameters only, in contrast to the results obtained with acetone as the precipitant. The present findings are used to discuss the necessity of ternary interaction parameters and possibilities for their calculation from known binary interaction parameters. (C) 2000 Elsevier Science Ltd. All rights reserved.},
language = {English},
number = {24},
journal = {Polymer},
author = {Barth, C. and Wolf, B. A.},
month = nov,
year = {2000},
keywords = {polystyrene, systems, equilibria, dimethylformamide, headspace-gas chromatography, polyethersulfone and polysulfone, ternary interaction parameters},
pages = {8587--8596},
}
@article{eckelt_polydispersity_2000,
title = {Polydispersity effects on the phase diagram of the system chloroform/poly-{L}-(lactic acid)/poly(methyl methacrylate) and morphology of {PLA}/{PMMA} films},
volume = {171},
issn = {0378-3812},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000089031000017&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0378-3812(00)00363-0},
abstract = {Cloud point curve, critical composition and several critical coexistence curves were measured at 25 degrees C for the ternary system poly-L-(lactic acid) (PLA), poly(methyl methacrylate) (PMMA) - where both polymers exhibit broad molecular weight distributions - and the common solvent chloroform; In contrast to the situation encountered in the absence of the second polymer both branches of the critical coexistence curves are located without any doubt inside the miscibility gap as defined by the cloud point curve. This unexpected experimental finding is corroborated by model calculations on the basis of continuous thermodynamics. The removal of solvent from the ternary mixtures yields films of different morphology, depending on the particular path through the metastable or unstable regions of the phase diagram. The structures observed by means of optical microscopy confirm the theoretically postulated phase separation mechanisms. (C) 2000 Elsevier Science B.V. All rights reserved.},
language = {English},
number = {1-2},
journal = {Fluid Phase Equilibria},
author = {Eckelt, J. and Enders, S. and Goncalves, M. D. and Queiroz, D. P. and Wolf, B. A.},
month = may,
year = {2000},
keywords = {behavior, solvent, blends, mixtures, derivatives, flory-huggins theory, gibbs energy, homopolymers, phase equilibria, tie lines},
pages = {219--232},
}
@article{schuld_solvent_2001,
title = {Solvent quality as reflected in concentration- and temperature-dependent {Flory}-{Huggins} interaction parameters},
volume = {39},
issn = {0887-6266},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000167186500004&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/1099-0488(20010315)39:6<651::Aid-Polb1039>3.0.Co;2-1},
abstract = {Flory-Huggins interaction parameters (chi) between poly(dimethylsiloxane) (weight-average molecular weight = 152 kg/mol) and various solvents (methyl ethyl ketone, toluene and n-octane) were determined as a function of composition and temperature with vapor-pressure measurements. These data, complemented by independent information for dilute and very concentrated solutions, serve as the basis for a discussion of solvent quality via different theoretical relations. Regardless of polymer concentration, the chi values fall from methyl ethyl ketone via toluene to n-octane, the ketone being the worst solvent and the hydrocarbon being the best solvent. The variation of chi with composition and temperature is complex. Within the range of moderate polymer concentrations, the influences of composition decrease with increasing solvent quality. Additional effects become noticeable at the ends of the composition scale. The enthalpy parts (chi (H)) and entropy parts (chi (S)) of the Flory-Huggins interaction parameter, obtained from chi (T), vary considerably with composition and change their sign in some cases; these constituents of the Flory-Huggins interaction parameter do not permit a direct assessment of solvent quality. A clear-cut picture is, however, regained with a comparison of the interdependence of chi (S) and chi (H). The elimination of explicit concentration influences re-establishes the order in the solvent quality setup via chi. (C) 2001 John Wiley \& Sons, Inc.},
language = {English},
number = {6},
journal = {Journal of Polymer Science Part B-Polymer Physics},
author = {Schuld, N. and Wolf, B. A.},
month = mar,
year = {2001},
keywords = {thermodynamics, blends, headspace gas chromatography, interaction parameters, binary polymer-solutions, chain-length, concentration influences, double-lattice model, gas-chromatography, solvent quality, temperature influences},
pages = {651--662},
}
@article{imre_effect_2001,
title = {On the effect of pressure on the phase transition of polymer blends and polymer solutions: {Oligostyrene}-n-alkane systems},
volume = {3},
issn = {1463-9076},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000167578700026&action=retrieve&mode=FullRecord},
doi = {Doi 10.1039/B008406i},
abstract = {Critical temperatures of some binary solutions of weakly interacting low molecular weight polystyrenes dissolved in linear alkanes (oligoethylenes) were measured over the range 0.1 to 100 MPa. While (dT/dP)(crit) along the upper critical solution (UCS) locus for a "typical blend'' is positive, and for the "typical solution'' can be either positive or negative (but is usually negative), there is no essential difference between blend and solution. Rather, the difference in sign is a consequence of the location of the hypercritical point (that point in (T,P)(crit) space where (dT/dP)(crit) changes sign, [(dT/dP)(crit)=0 and (T/dP(2))(crit){\textgreater}0], also called the double critical point, DCP), which is normally found at P {\textgreater}0 for solutions but is shifted to P {\textless}0 for blends.},
language = {English},
number = {6},
journal = {Physical Chemistry Chemical Physics},
author = {Imre, A. R. and Melnichenko, G. and Van Hook, W. A. and Wolf, B. A.},
year = {2001},
keywords = {dependence, polystyrene solutions, behavior, miscibility, thermodynamics, mixtures, solvent quality, liquid-liquid equilibria, negative-pressure, solubility},
pages = {1063--1066},
}
@article{welge_reduction_2001,
title = {Reduction of the interfacial tension between 'immiscible' polymers: to which phase one should add a compatibilizer},
volume = {42},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000166619700019&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0032-3861(00)00781-3},
abstract = {The reduction of interfacial tension a between polyethylene oxide (PEO) and polypropylene oxide (PPO) by either a triblock copolymer EO-PO-EO or a diblock copolymer styrene-EO was studied by means of the pendant drop method from 70 to 120 degreesC. Time independent data correspond to stationary states and do not represent equilibrium information. The addition of the compatibilizer to the PPO phase is approximately twice as efficient as the addition to the PEO phase for both block copolymers. Knowing the concentration dependence of sigma for one of the coexisting phases it is possible to forecast the effects resulting from the addition of the other phase by means of model considerations based on the partition coefficient of the additive and the ratio of the viscosities of the coexisting phases. (C) 2001 Elsevier Science Ltd. All rights reserved.},
language = {English},
number = {8},
journal = {Polymer},
author = {Welge, I. and Wolf, B. A.},
month = apr,
year = {2001},
keywords = {interfacial tension, diblock copolymers, homopolymer blends, equilibria, mixtures, architecture, profile, block-copolymers, compatibilizer, incompatible polymers, poly(ethylene oxide), random copolymers, stationary states},
pages = {3467--3473},
}
@article{hagenaars_characterization_2001,
title = {Characterization of melt-polymerized polycarbonate: preparative fractionation, branching distribution and simulation},
volume = {42},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000169119900021&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0032-3861(01)00250-6},
abstract = {Melt-polymerized bisphenol-A polycarbonate materials characterized by a low degree of branching were fractionated according to molecular weight by the continuous polymer fractionation (CPF) method. The distribution of two types of end-groups and in-chain salicylate moieties arising from thermal rearrangement reactions were assessed across the molecular weight distribution by analysis of the fractions. Experimentally determined branching densities of the fractions agreed well with a molecular simulation based on a random sampling polycondensation model. Both simulation and experiments showed that the branching density increases with molecular weight in the experimentally accessible range. (C) 2001 Elsevier Science Ltd. All rights reserved.},
language = {English},
number = {18},
journal = {Polymer},
author = {Hagenaars, A. C. and Pesce, J. J. and Bailly, C. and Wolf, B. A.},
month = aug,
year = {2001},
keywords = {chromatography, bisphenol-a, diphenyl carbonate, melt polymerization, molecular-weight distribution, polycarbonate},
pages = {7653--7661},
}
@incollection{barth-wiedmann_phase_2004,
series = {Research {Report}},
title = {Phase {Behavior} of {Quaternary} {Polymer} {Solutions}},
booktitle = {{DFG}-{SSP} "{Thermodynamic} {Properties} of {Complex} {Fluid} {Mixtures}" {Research} {Report}},
publisher = {VCh Wiley},
author = {Barth-Wiedmann, Claudia and Wünsch, Matthias and Wolf, Bernhard Anton},
editor = {Maurer, Gerd},
year = {2004},
pages = {381--402},
}
@article{posharnowa_polymer-polymer_2001,
title = {Polymer-polymer interaction parameters for homopolymers and copolymers from light scattering and phase separation experiments in a common solvent},
volume = {115},
issn = {0021-9606},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000172129300048&action=retrieve&mode=FullRecord},
doi = {Doi 10.1063/1.1412867},
abstract = {The thermodynamic behavior of the quaternary system DMAc/PS/PAN/SAN and of all its solvent containing subsystems [DMAc: dimethylacetamide, PS: polystyrene, PAN: polyacrylonitrile, SAN: P(S-ran-AN)] was studied in terms of second virial coefficients and phase separation in the range of moderate polymer concentrations. The most remarkable finding consists in fundamental discrepancies between the Flory-Huggins parameters obtained for the interaction between the segments of polymer X and polymer Y either straightforwardly from the light scattering experiments (ranging from -0.88 to -0.14) and that resulting from the modeling of the measured phase diagrams (+0.01 to +0.33) or from solubility parameter theory (+0.03 to +1.92). The reasons for the disagreement even in the sign of the parameters are discussed in terms of A(2)(XY), the second osmotic virial coefficients referring to the opening of intermolecular contacts between X and Y by the insertion of solvent and in terms of W-2, the normalized excess Gibbs energy of contact formation between the two types of solute in the concentration region of pair interaction according to X-X+Y-Y --{\textgreater} 2X-Y. The pair interaction coefficient W-2 results negative for PS/SAN, but positive for PAN/SAN and for PAN/PS. A theoretical explanation of this unexpected result is offered. (C) 2001 American Institute of Physics.},
language = {English},
number = {20},
journal = {Journal of Chemical Physics},
author = {Posharnowa, N. and Schneider, A. and Wunsch, M. and Kuleznew, V. and Wolf, B. A.},
month = nov,
year = {2001},
keywords = {polystyrene, blends, chromatography, compatibility, mixtures, derivatives, poly(ethylene oxide), crystallization, poly(methyl methacrylate), self-diffusion coefficients},
pages = {9536--9546},
}
@article{schnell_excess_2001,
title = {Excess viscosity and glass transition},
volume = {42},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000170217200013&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0032-3861(01)00372-X},
abstract = {Literature data on the viscosity of solutions of poly(butyl methacrylate) (PBMA) and poly(methyl methacrylate) (PMMA) in diethyl phthalate (DEP) for different temperatures, including the range around and below T-g, the glass transition temperatures of the pure polymers, were evaluated by means of an approach that uses surface fractions as composition variables. The discussion of these results together with information on solutions of the isomeric polymers, poly(vinyl acetate) (PVAc) and poly(methyl acrylate) (PM(A)), in the same solvent testifies that the previously published relations remain valid for T {\textless} T-g. They enable the determination of viscosities of the pure polymers below T-g by extrapolating the solution data to vanishing solvent content. The temperature dependencies of the data obtained in this manner demonstrate that the viscosity of PBMA rises upon cooling as expected according to the WLF equation, whereas the increase is lower by several orders of magnitude for PMMA and PVAc. These observations and the temperature dependencies of the system-specific parameters of the present approach are discussed in detail. (C) 2001 Elsevier Science Ltd. All rights reserved.},
language = {English},
number = {21},
journal = {Polymer},
author = {Schnell, M. and Wolf, B. A.},
month = oct,
year = {2001},
keywords = {polymer, glass transition, mixing rule, molecular-surfaces, solution viscosities},
pages = {8599--8605},
}
@article{schneider_apparatus_2002,
title = {An apparatus for automated turbidity titrations and its application to copolymer analysis and to the determination of phase diagrams},
volume = {203},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000174533000011&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/1521-3935(20020301)203:4<705::Aid-Macp705>3.0.Co;2-7},
abstract = {We present an apparatus for quick and reliable determinations of transmissions curves specifying the dependance of the light intensity (normalized to that of the primary beam) passing a test solution on amount of standard solution added. This device is used for two different purposes, namely for the analysis of copolymers (here: poly(vinyl alcohol), which is a copolymer since it is produced via incomplete hydrolysis if poly(vinyl acetate)) and for the determination of phase diagrams (here: toluene/ethonol/polydimethylsiloxane). The most important observation in the field of copolymer analysis consists in the possibility to obtain information on the widths of the chemical distribution. Adequate turbidimetric titrations reveal pronounced differences between samples that should according to their standard characterization with respect to average chain length and average chemical composition be identical. the central message regarding phase diagrams is that the evaluation of transmission curves with respect to macroscopic demixing is greatly simplified by the fact that the phase separation of a given system takes place within a small band of transmission values, independent of the composition of the mixture.},
language = {English},
number = {4},
journal = {Macromolecular Chemistry and Physics},
author = {Schneider, A. and Wunsch, M. and Wolf, B. A.},
month = mar,
year = {2002},
keywords = {phase diagrams, automated turbidimetric titration, copolymer characterization, mixed solvents, poly(vinyl alcohol)},
pages = {705--711},
}
@article{gosch_molar_2002,
title = {Molar mass distribution and size of hydroxyethyl starch fractions obtained by continuous polymer fractionation},
volume = {54},
issn = {0038-9056},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000178119000001&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/1521-379x(200209)54:9<375::Aid-Star2222375>3.0.Co;2-G},
abstract = {By the use of continuous polymer fractionation (CPF) the initial polymer can be separated into fractions of different molar masses, which makes it possible to obtain hydroxyethyl starch (HES) fractions tailor-made for specific application. Two samples of HES (HES A and HES B) were fractionated by means of CPF. By size-exclusion chromatography-multi-angle laser light-scattering-differential refractive index (SEC/MALLS/DRI) measurements it was shown that CPF is able to remove the low-molar-mass components and to adjust the samples to various desired molar masses with lower polydispersities than the original samples. In terms of the weight-average mean, molar mass M-W, the sol fractions have smaller molar masses than the starting sample, whilst the gel fractions have higher molar masses. Furthermore the radius of gyration R-G could be determined for the initial sample HES B with 19.7 and 19.4 nm and also for some of its fractions. However, no general R-G-M-W relationship could be established for the HES samples fractionated using CPF. This is probably due to the complex branched structure of amylopectin. M-W and M-W/M-n, of the six fractions obtained from HES A with M-W = 161,000 g/mol and M-W/M-n = 4.7 ranged from 19,000 to 362,000 g/mol with M-W/M-n from 1.8 to 3.1. The molar masses of the four fractions obtained from HES B with M-W = 460,000 g/mol and M-W/M-n = 6.0 were between 18,000 and 680,000 g/mol with M-W/M-n from 1.7 to 4.8 or between 202,000 and 1,005,000 g/mol with M-W/M-n from 2.7 to 4.7 depending on fractionation strategy.},
language = {English},
number = {9},
journal = {Starch-Starke},
author = {Gosch, C. I. and Haase, T. and Wolf, B. A. and Kulicke, W. M.},
month = sep,
year = {2002},
keywords = {light-scattering, hydroxyethyl starch, molar mass distribution, polymer fractionation, size-exclusion chromatography},
pages = {375--384},
}
@article{hagenaars_preparative_2002,
title = {Preparative fractionation and characterization of polycarbonate/eugenol-siloxane copolymers},
volume = {43},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000174631600010&action=retrieve&mode=FullRecord},
doi = {Pii S0032-3861(02)00052-6 Doi 10.1016/S0032-3861(02)00052-6},
abstract = {Bisphenol-A polycarbonate/eugenol-siloxane copolymers were fractionated at the preparative scale by the continuous polymer fractionation (CPF) technique. It is the first example of copolymer fractionation by CPF. The distribution of siloxane species across the fractions was assessed for copolymers differing in initial siloxane concentration and block length. On- and off-line combinations of size exclusion chromatography and infrared spectroscopy were used to analyze chemical composition (CC) of the unfractionated samples across the molecular weight distribution enabling comparison with the fractions. A polycarbonate-siloxane copolymer containing 10 wt\% of very short siloxane blocks (dp = 2) was fractionated solely according to molecular weight (MW). By contrast, a copolymer containing 5 wt\% siloxane blocks with a larger degree of polymerization (dp = 23) was fractionated according to MW, as well as to CC. This 'chemical drift' effect for the larger siloxane block length can be ascribed to large solubility differences of low MW chains, which drastically vary in composition according to the (small) number of siloxane blocks they contain. (C) 2002 Elsevier Science Ltd. All rights reserved.},
language = {English},
number = {9},
journal = {Polymer},
author = {Hagenaars, A. C. and Bailly, C. and Schneider, A. and Wolf, B. A.},
month = apr,
year = {2002},
keywords = {continuous polymer fractionation, bisphenol-a, polycarbonate, siloxane},
pages = {2663--2669},
}
@article{hugenberg_synthesis_2002,
title = {Synthesis and large scale fractionation of non-linear polymers: brushes and hyperbranched polymers},
volume = {307},
issn = {0022-3093},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000178038100102&action=retrieve&mode=FullRecord},
doi = {Pii S0022-3093(02)01559-4 Doi 10.1016/S0022-3093(02)01559-4},
abstract = {Polymer brushes with poly(methyl methacrylate) (PMMA) backbone and polystyrene side chains were synthesized by radical polymerization of omega-methacryloyl-polystyrene macromonomers. Hyperbranched PMMA was obtained by means of self-condensing group transfer copolymerization of methyl methacrylate with an initiator-monomer containing a polymerizable methacryloyl moiety and an initiating silylketeneacetal function. Both non-linear products were fractionated using the method of continuous polymer fractionation, consisting in a particular type of continuous countercurrent extraction. The combination of methyl ethyl ketone (solvent) with acetone (AC) (precipitant) turned out to be suitable for the fractionation of the polymer brushes; in case of the hyperbranched material AC served as the solvent component and methanol as the precipitant. The achieved fractionation was checked by means of GPC measurements and in case of the polymer brushes also by AFM, where the differences in the size of the macromolecules became clearly visible. (C) 2002 Elsevier Science B.V. All rights reserved.},
language = {English},
journal = {Journal of Non-Crystalline Solids},
author = {Hugenberg, N. and Loske, S. and Muller, A. H. E. and Schartl, W. and Schmidt, M. and Simon, P. F. W. and Strack, A. and Wolf, B. A.},
month = sep,
year = {2002},
pages = {765--771},
}
@article{loske_fractionation_2003,
title = {Fractionation of cellulose acetate for the investigation of molecular weight influences on the morphology of membranes},
volume = {214},
issn = {0376-7388},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000181992000006&action=retrieve&mode=FullRecord},
doi = {Doi 10.1016/S0376-7388(02)00549-5},
abstract = {Cellulose acetate (CA) with an apparent weight average molar mass, M-w, of 150 kg/mol was fractionated with respect to M by means of the mixed solvent methyl acetate (MeAc)/2-propanol (2-POH) applying a new method that uses spinning nozzles to promote the rapid attainment of phase equilibria. Two of the fractions obtained in this manner were employed to prepare membranes from solutions in methyl acetate with 2-propanol as coagulating agent. Electron n-dcrographs demonstrate that the molar mass of CA influences the morphology of the membranes markedly under otherwise identical conditions. For M-w = 128 kg/mol, one obtains considerably denser structures than for M-w* = 263 kg/mol; furthermore, the pores are considerably less interconnected in the former than in the latter case. The efficiency of the fractionation process and the reasons for the differences in membrane structure are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.},
language = {English},
number = {2},
journal = {Journal of Membrane Science},
author = {Loske, S. and Goncalves, M. D. C. and Wolf, B. A.},
month = apr,
year = {2003},
keywords = {continuous polymer fractionation, cellulose acetate, membrane preparation and structure},
pages = {223--228},
}
@article{wunsch_interfacial_2002,
title = {Interfacial tension between coexisting polymer solutions in mixed solvents and its correlation with bulk thermodynamics: phase equilibria (liquid/gas and liquid/liquid) for the system toluene/ethanol/{PDMS}},
volume = {43},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000177203900022&action=retrieve&mode=FullRecord},
doi = {Pii S0032-3861(02)00325-7 Doi 10.1016/S0032-3861(02)00325-7},
abstract = {Vapor pressures, phase equilibria and interfacial tensions sigma were measured for solutions of poly(dimethylsiloxane) (PDMS, M-w = 75 kg/mol and M. = 50 kg/mol) in mixed solvents of toluene (TL) and ethanol (EtOH) at 30, 40, 50 and 60 degreesC. The experimental ternary phase diagrams can be modeled quantitatively from the determined concentration and temperature dependent binary interaction parameters chi(ij) if the experimentally inaccessible composition dependence o chi(EtOH)/(PDMS) is adjusted. The relations between o, and the equation of state of the system differ from that applying to single solvents. The exponents as well as the amplitude prefactors of the corresponding scaling laws (e.g. the dependencies of o, on the length of the tie lines or on the hump energy, i.e. on the intrusion into the two phase regime quantified in terms of Gibbs energies) change considerably with temperature. However, this variation can be reduced significantly by normalizing the independent variables. Dividing the length of the tie lines by the length for the corresponding binary subsystem proves more efficient than the distance of these tie lines from the critical point of the ternary system relative to the maximum distance of the binary subsystem. A combined normalization does not improve the situation. (C) 2002 Elsevier Science Ltd. All rights reserved.},
language = {English},
number = {18},
journal = {Polymer},
author = {Wunsch, M. and Wolf, B. A.},
month = aug,
year = {2002},
keywords = {dependence, interfacial tension, diagrams, equation, interaction parameters, 2 homopolymers, corresponding copolymer, derivatives, highly incompatible polymers, gibbs energy, double-lattice model, mixed solvents, vapor pressures},
pages = {5027--5034},
}
@article{madbouly_equilibrium_2002,
title = {Equilibrium phase behavior of polyethylene oxide and of its mixtures with tetrahydronaphthalene or/and poly(ethylene oxide-block-dimethylsiloxane)},
volume = {117},
issn = {0021-9606},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000178317300053&action=retrieve&mode=FullRecord},
doi = {Doi 10.1063/1.1507111},
abstract = {Liquid/solid and liquid/liquid (LL) transition temperatures were measured by means of an automated device that monitors the light passing through the systems as a function of T at different constant cooling or heating rates q. For pure polyethylene oxide (PEO) crystallization and melting temperatures depend on {\textbackslash}q{\textbackslash}(0.3) and become identical at the equilibrium transition temperature T-m=61.0 degreesC in the limit of infinitely slow cooling/heating. The reduction of T-m for PEO dissolved in tetrahydronaphthalene (THN) yields information on the Flory-Huggins interaction parameter xi between these two compounds; xi results negative and decreases markedly with rising polymer concentration. A tentative explanation for this finding is offered. The binary blend between PEO and poly(ethylene oxide-block-dimethylsiloxane) (COP, T-m=0 degreesC) exhibits a much more complex phase diagram than the system THN/PEO. An additional and extended miscibility gap (LL) is observed at high temperatures and there is no experimental evidence of an eutectic. From the details of the phase diagram we conclude that the EO-rich block copolymer can incorporate small amounts of PEO and form mixed crystals. The existence of two three-phase lines is postulated. The melting behavior of PEO in the ternary system THN/COP/PEO (constant weight fraction of PEO) fits well into the other results. (C) 2002 American Institute of Physics.},
language = {English},
number = {15},
journal = {Journal of Chemical Physics},
author = {Madbouly, S. A. and Wolf, B. A.},
month = oct,
year = {2002},
keywords = {thermodynamics, blends, spinodal decomposition, crystallization, poly(methyl methacrylate), binary polymer mixtures, melting-point depression, morphology control, poly(vinylidene fluoride)},
pages = {7357--7363},
}
@article{silva_thermodynamics_2003,
title = {Thermodynamics of pseudo-ternary systems as a tool to predict the morphologies of cellulose acetate/polystyrene blends cast from tetrahydrofuran solutions},
volume = {44},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000180585400021&action=retrieve&mode=FullRecord},
doi = {Pii S0032-3861(02)00869-8 Doi 10.1016/S0032-3861(02)00869-8},
abstract = {The demixing behavior of the ternary system THF/CA/PS (tetrahydrofuran/cellulose acetate/polystyrene) was investigated at 25degreesC. Cloud point measurements show that the system exhibits a large miscibility gap caused by the incompatibility of CA and PS. Both ends of the experimentally determined tie lines are located inside the two-phase area of the phase diagram. By means of the measured critical composition of the ternary system and the Flory-Huggins interaction parameters published for two of the binary subsystems (X-CA/(THF) = 0.442 and X-PS/(THF) = 0.475) the polymer/polymer interaction parameter was adjusted (directly minimizing the Gibbs energy) to X-CA/(PS) = 0.057. These thermodynamic data were used to calculate the extension of the metastable and the unstable regions of the phase diagram. This procedure permits a realistic prediction of the morphologies of the (solvent-free) blends from the location of the starting composition of the casting solutions in the Gibbs phase triangle, as demonstrated by means of optical micrographs and field emission scanning electron micrographs. (C) 2002 Published by Elsevier Science Ltd.},
language = {English},
number = {4},
journal = {Polymer},
author = {Silva, G. A. and Eckelt, J. and Goncalves, M. C. and Wolf, B. A.},
month = feb,
year = {2003},
keywords = {solvent, phase-diagrams, derivatives, gibbs energy, cellulose acetate, copolymer, morphology, ternary system},
pages = {1075--1080},
}
@article{eckelt_formation_2003,
title = {Formation of micro- and nano-spheric particles (filter dust) during the preparation of cellulose acetate membranes},
volume = {212},
issn = {0376-7388},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000180691400006&action=retrieve&mode=FullRecord},
doi = {Pii S0376-7388(02)00454-4 Doi 10.1016/S0376-7388(02)00454-4},
abstract = {Membranes were prepared from six samples of cellulose acetate (CA) differing in their average molecular weight (75-260 kg/mole) and molecular weight distribution using methyl acetate as solvent and 2-propanole as precipitant. The routes through the phase diagram and the evaporation times were varied in these experiments. Electron microscopy demonstrates that the amount of filter dust (CA particles deposited on the membrane surface) decreases as the fraction of low molecular weight material in the starting polymer becomes less. For low average molar mass of CA and moderate polymer concentrations in the casting solution the dust consists of individual spheres of relatively uniform size (1-2 mum) which cover the surface in a number of layers. With rising molar mass of the polymer the dust particles consist increasingly of strings of cohering and deformed beads of comparable size. Under these condition, some considerably smaller particles (less than or equal to0.1 mum) are also formed. Possible mechanisms of filter dust formation are discussed and measures for its prevention are proposed. (C) 2002 Elsevier Science B.V. All rights reserved.},
language = {English},
number = {1-2},
journal = {Journal of Membrane Science},
author = {Eckelt, J. and Loske, S. and Goncalves, M. C. and Wolf, B. A.},
month = feb,
year = {2003},
keywords = {cellulose acetate, 2-propanole, filter dust, microspheres},
pages = {69--74},
}
@article{jiang_pressure-induced_2002,
title = {Pressure-induced compatibility in {PEO}/{P}({EO}-b-{DMS}) polymer mixtures},
volume = {35},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000176814600001&action=retrieve&mode=FullRecord},
doi = {Unsp Ma012054e Doi 10.1021/Ma012054e},
language = {English},
number = {15},
journal = {Macromolecules},
author = {Jiang, S. C. and Jiang, W. and Wolf, B. A. and An, L. J. and Jiang, B. Z.},
month = jul,
year = {2002},
keywords = {dependence, miscibility, temperature, systems, thermodynamics, blends, block-copolymer melts, compressibility, neutron-scattering, solution phase equilibria},
pages = {5727--5730},
}
@article{madbouly_shear-induced_2003,
title = {Shear-induced crystallization and shear-induced dissolution of poly(ethylene oxide) in mixtures with tetrahydronaphthalene and oligo(dimethyl siloxane-b-ethylene oxide)},
volume = {204},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000182127000006&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.200390007},
abstract = {Cloud point temperatures (T-cp) and crystallization temperatures, (T-I/s) were measured at different constant shear rates for the ternary system tetrahydronaphthalene/polyethylene oxide/oligo(dimethyl siloxane-b-ethylene oxide) using a rheo-optical device and in the case of T-1/s additionally a viscometer: This system enables for the first time a joint investigation of both transitions with a given mixture. Shear favors the-homogeneous liquid state and the, formation of crystals. T-cp (liquid/liquid demixing, UCST) shifts to lower and T-1/s (liquid/solid, segregation of PEO) to higher temperatures by several degrees as the shear rate, (gamma) over dot, is increased up to 500 s(-1). The normalized shift in T-cp fits well into previous results for high molecular weight blends, oligomer mixtures; polymer solutions in single solvents and low molecular weight mixtures. A phase separated near critical blend was examined 1 K below its T-cp by means of-a shear cell (Linkam) in the quiescent state and under shear with respect to its morphology. Upon an increase in (gamma) over dot one observes a transition from the co-continuous structures existing in the quiescent state via deformed and oriented particles to string like morphologies. Finally, at sufficiently high shear rates the mixture becomes homogeneous and structures can no longer be seen under the microscope. The morphologies developing after the secession of shear are pointing to pronounced influences of the flow history of the system on the final structure of two phase blends.},
language = {English},
number = {3},
journal = {Macromolecular Chemistry and Physics},
author = {Madbouly, S. A. and Wolf, B. A.},
month = mar,
year = {2003},
keywords = {flow, phase separation, blends, light-scattering, diagrams, molecular-weight, separation, common solvent, highly incompatible polymers, crystallization, critical fluids, phase-behavior, shear effects, ternary mixtures},
pages = {417--424},
}
@article{imre_liquid-liquid_2002,
title = {Liquid-liquid phase equilibria in polymer solutions and polymer mixtures},
volume = {181},
issn = {1022-1360},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000176238500037&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/1521-3900(200205)181:1<363::Aid-Masy363>3.0.Co;2-N},
abstract = {The pressure dependence of liquid-liquid equilibria in weakly interacting binary macromolecular systems (homopolymer solutions and blends) will be discussed. The common origin of the separate high-temperature/low-temperature and high-pressure/low-pressure branches of demixing curves will be demonstrated by extending the study into the region of metastable liquid states including the undercooled, overheated and stretched states (i.e. states at negative pressures). The seemingly different response of the UCST-branch of solutions and blends when pressurized (pressure induced mixing for most polymer solutions, pressure induced demixing for most blends) will be explained in terms of the location of a hypercritical point found either at positive (most solutions) or negative pressure (most blends). Further, it is shown that the pressure dependence of demixing of homopolymer solutions and blends may be described using a 'master-curve' which, however, is sometimes partly masked by degradation or by vapour-liquid and/or solid-liquid phase transitions. Experimental results demonstrating the extension of liquid-liquid phase boundary curves into the metastable regions will be presented, and the existence of solubility islands in the vicinity of the hypercritical points discussed.},
language = {English},
journal = {Macromolecular Symposia},
author = {Imre, A. R. and Van Hook, W. A. and Wolf, B. A.},
month = may,
year = {2002},
keywords = {system, polystyrene solutions, behavior, blend miscibility, pressure-dependence, negative-pressure, isotope, methylcyclohexane, supercritical-fluid, tension},
pages = {363--372},
}
@article{kuleznev_intermolecular_2002,
title = {On intermolecular interactions in solutions of polymer blends},
volume = {44},
issn = {1560-0904},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000175464200005&action=retrieve&mode=FullRecord},
abstract = {Phase diagrams for solutions of blends of a series of homopolymers and random polymers were obtained and compared with the dependences of the second virial coefficient A(2) and intensity of excess light scattering R-90" on the ratio of the polymer concentrations in solution. The mutual solubility of polymers correlates with the values of R-90" and A(2): the larger the deviations of these parameters from the corresponding additive values, the lower the thermodynamic compatibility of the polymers. Introduction of a third polymer into a binary blend enhanced the interaction between unlike molecules, as manifested in a decrease in the deviation of A(2) and R-90" from their values predicted with the additivity rule, thus indicating an increased mutual solubility of polymers in the ternary system.},
language = {English},
number = {3-4},
journal = {Polymer Science Series B},
author = {Kuleznev, V. N. and Wolf, B. and Pozharnova, N. A.},
month = apr,
year = {2002},
keywords = {phase-separation},
pages = {67--70},
}
@article{bercea_chain_2003,
title = {Chain connectivity and conformational variability of polymers: {Clues} to an adequate thermodynamic description of their solutions, 1 - {Dilute} solutions},
volume = {204},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000184527900001&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.200350001},
abstract = {This is the first of two parts investigating the Flory-Huggins interaction parameter, chi, as a function of composition and chain length. Part 1 encompasses experimental and theoretical work. The former comprises the synthesis of poly(dimethylsiloxane)s with different molar mass and the measurements of their second osmotic virial coefficients. A(2) in solvents of diverse quality as a function of M via light scattering and osmotic pressures. The theoretical analysis is performed by subdividing the dilution process into two clearly separable steps. It yields the following expression for chi(o), the chi value in range of pair interaction chi(o) = alpha- zetalambda. The parameter alpha measures the effect of contact formation between solvent molecule sand polymer segments at fixed chain conformation, whereas the parameter zeta quantifies the contributions of the conformational changes taking place in response to dilution; zeta becomes zero for theta conditions. The influences of M are exclusively contained in the parameter lambda. The new relation is capable of describing hitherto incomprehensible experimental findings, like a diminution of chio with rising M. The evaluation of experimental information for different systems according to the established equation displays the existence of a linear interrelation between zeta and alpha, Part 2 of this investigation presents the generalization of the present approach to solutions of arbitrary composition and discusses the physical meaning of the parameters in more detail.},
language = {English},
number = {11},
journal = {Macromolecular Chemistry and Physics},
author = {Bercea, M. and Cazacu, M. and Wolf, B. A.},
month = jul,
year = {2003},
keywords = {molecular-weight, flory-huggins interaction parameter, poly(dimethylsiloxane), chain conformation, length, molecular weight influences, second osmotic virial coefficient, virial-coefficients},
pages = {1371--1380},
}
@article{wolf_chain_2003,
title = {Chain connectivity and conformational variability of polymers: {Clues} to an adequate thermodynamic description of their solutions, 2 - {Composition} dependence of flory-huggins interaction parameters},
volume = {204},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000184527900002&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.200350002},
abstract = {Full Paper: In Part 1 of this contribution we have reported how the Flory-Huggins interaction parameter chi can be {\textless}LF{\textgreater}modeled as a function of chain length within the composition range of pair interaction between the macromolecules by means of the three parameters alpha, zeta, {\textless}LF{\textgreater}and lambda. This contribution presents the extension of the {\textless}LF{\textgreater}approach to arbitrary volume fractions, phi, of the polymer and its application to published data on chi(phi). The resulting equation reads chi = alpha(1 - nuphi)(-2) - zeta(lambda + 2(1 - lambda)phi) and requires only the additional parameter nu to incorporate the composition dependence. Its employment to experimental data is very much facilitated by substituting for chi(o) (limiting value for phi --{\textgreater} 0); furthermore, the expression can in good approximation be simplified to chi approximate to (chi(o) + zetalambda)(1 - nu phi)(-2) - zetalambda(1 + 2phi). That is: only two parameters, nu and the product of zeta and lambda, need to be adjusted. This relation is capable of describing all types of composition dependencies reported in the literature, including the hitherto incomprehensible occurrence of pronounced minima in chi(phi). For a given system the evaluation of the chain length dependence of chi(o), reported in Part 1, and the present evaluation of the composition dependence of chi(o) yield the same data for the conformational response zeta. Similarly both types of measurements generate the same interdependence between zeta and alpha. The physical meaning of the different parameters and the reason for the observed correlations are discussed.},
language = {English},
number = {11},
journal = {Macromolecular Chemistry and Physics},
author = {Wolf, B. A.},
month = jul,
year = {2003},
keywords = {flory-huggins interaction parameter, composition dependence, conformational relaxation, temperature dependence},
pages = {1381--1390},
}
@article{wolf_critical_2002,
title = {Critical phenomena in solutions of the polystyrene-polyacrylonitrile random copolymer and its blends with polystyrene},
volume = {44},
issn = {0965-545X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000177513400016&action=retrieve&mode=FullRecord},
abstract = {The specifics of behavior of toluene solutions of a polystyrene-polyacrylonitrile random copolymer and its blends with polystyrene in the near-critical region in the vicinity of the cloud point is described. The effect of very small additions of polystyrene on the behavior of a PS-PAN solution in a poor solvent, represented by toluene, was studied. This effect may be explained by a high capability of PS macromolecules for concentrating near polystyrene-polyacrylonitrile heterophase associates or particles of a new phase. The thermodynamic incompatibility of the PS-PAN copolymer and PS causes a sharp increase in the phase separation temperature, thus increasing the region of two-phase systems in the phase diagram. The appearance of a viscosity minimum and other specific features of the shear behavior of the solutions are explained by the character of their structure in the near-critical region. The effect of the shear rate on the cloud point in these systems was also studied.},
language = {English},
number = {7},
journal = {Polymer Science Series A},
author = {Wolf, B. and Kuleznev, V. N. and Pozharnova, N. A.},
month = jul,
year = {2002},
keywords = {flow, polymer blends, shear},
pages = {767--772},
}
@article{eckelt_fractionation_2003,
title = {Fractionation of cellulose},
volume = {10},
issn = {0969-0239},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000183857700002&action=retrieve&mode=FullRecord},
doi = {Doi 10.1023/A:1023048422822},
abstract = {Cellulose samples with molecular weight distributions that are considerably narrower than those of the natural products can be obtained by at least three fundamentally different routes. (i) Synthesis of easily soluble derivatives, fractionation by means of well-established methods and subsequent regeneration, (ii) selective extraction of short chains from activated cellulose, using solvents of suitable marginal quality,and (iii) partition of the homologs between two coexisting phases formed by the demixing of homogeneous solutions. All,three methods can be applied successfully. However, the efforts in terms of labor and required solvent differ considerably. Most of the experiments were performed with the following three cellulose samples: Avicel (M-w = 30 kg mol(-1), U = (M-w/M-n) - 1 = 2.0), Solucell (M-w = 230 kg mol(-1), U = 1.8), and Stockstadt (M-w = 320 kg mol(-1), U = 5.7). Options (ii) and (iii) emerged most promising for large scale fractionation. The mixed solvent consisting of DMAc and LiCl turned out to be particularly versatile in both cases. In the pure state it can be used for incremental extraction (yielding quick access to orienting information on the width of the molecular weight distribution) as well as for one-step extraction. In combination with suitable precipitants (like acetone) it enables the realization of the coexistence of two liquid phases required with route (iii). One obstacle for fractionation that all methods share is the high viscosity of cellulose solutions. With the last method it is possible to mitigate this limitation considerably by the use of spinning nozzles for the mixing of feed and extracting agent.},
language = {English},
number = {1},
journal = {Cellulose},
author = {Eckelt, J. and Stryuk, S. and Wolf, B. A.},
month = mar,
year = {2003},
keywords = {fractionation, continuous polymer fractionation, phase diagram, cellulose tmsc, chloride, molecular weight distribution, n,n-dimethylacetamide, unsubstituted cellulose},
pages = {5--12},
}
@article{badiger_shear_2003,
title = {Shear induced demixing and rheological behavior of aqueous solutions of poly({N}-isopropylacrylamide)},
volume = {204},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000182265000007&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.200390026},
abstract = {The interrelation between the phase separation behavior and the rheological performance of aqueous solutions of high molecular weight ((M) over bar (w) = 1 600 kg/mol) poly(N-isopropylacrylamide) was investigated. The system demixes upon heating and the cloud point temperatures, T-cp decreases steadily with rising polymer concentration up to 10 wt.-\%. The application of shear supports phase separation and reduces T-cp markedly. This observation is interpreted in terms of destruction of intersegmental clusters formed in the quiescent state owing to favorable interactions. Intrinsic viscosities and Huggins coefficients as well as the viscosities, eta at higher polymer concentrations are closely connected with the thermodynamic conditions. [eta] decreases by almost two orders of magnitude upon heating, whereas the corresponding increase of k(H) is less pronounced. The eta values (constant shear rate) of the moderately concentrated solutions as function of T pass a maximum at the corresponding phase separation temperatures. The existence of clusters also manifests in terms of stress overshoot and of particularities observed with solutions that are sheared for the first time.},
language = {English},
number = {4},
journal = {Macromolecular Chemistry and Physics},
author = {Badiger, M. V. and Wolf, B. A.},
month = mar,
year = {2003},
keywords = {phase-separation, polymer-solutions, blends, gels, hydrophobic associations, lcst, phase behavior, pnipam, shear induced demixing, transition},
pages = {600--606},
}
@article{madbouly_crystallization_2004,
title = {Crystallization kinetics of poly(ethylene oxide) from its melt and from mixtures with tetrahydronaphthalene and oligo(ethylene oxide-block-dimethylsiloxane)},
volume = {42},
issn = {0887-6266},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000189381100009&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/Polb.10483},
abstract = {The crystallization of poly(ethylene oxide) (PEO) from the pure state and from its mixtures with oligo(dimethyl siloxane-b-ethylene oxide) (COP) and tetrahydronaphthalene (THN) was investigated. The crystallization kinetics was studied isothermally and nonisothermally with an automated device that monitored the light passing through the corresponding liquids as functions of time and/or temperature. The rate was strongly influenced by the concentration of COP in the mixture. A substantial decrease in the induction time (the time required for the onset of crystallization) and a considerable shift in the crystallization temperature (the transition from a liquid state to a solid state) to higher temperatures were observed as the concentration of COP rose. This behavior was attributed to the differences in the interaction parameters of PEO with THN and COP. The isothermal crystallization kinetics was analyzed on the basis of the Avrami equation. Modified approaches (Avrami and Ozawa) were used for the evaluation of nonisothermal crystallization. In the initial state of crystallization, a power law held true for the augmentation of the radii of spherulites with time for all mixtures, regardless of the concentration of COP. Different spherulitic morphologies were observed, depending on the COP concentration. With rising COP contents, the structures changed from being needlelike to being compact. These findings were all examined in terms of the isothermal variation of the degree of supercooling resulting from changes in the compositions of the mixtures. (C) 2004 Wiley Periodicals, Inc.},
language = {English},
number = {5},
journal = {Journal of Polymer Science Part B-Polymer Physics},
author = {Madbouly, S. A. and Wolf, B. A.},
month = mar,
year = {2004},
keywords = {behavior, poly(ethylene oxide), morphology, avrami analysis, crystallization kinetics, fractions, growth, growth rate, high polymers, molecular-complex, non-isothermal crystallization, nonisothermal crystallization, polyethylene oxide, single-crystals, spherulitic morphology, three component system},
pages = {820--829},
}
@patent{eckelt_spinning_nodate,
address = {worldwide},
title = {Spinning process and apparatus for the technical fractionation of oligomers and polymers},
language = {English},
assignee = {Wolf, Bernhard Anton},
number = {PCT/EP03/00755 info from March 2007 U.S. application no. 10/897,452 Australia application no. 2003206777 Canada application no. 2,472,375 China application no. 03802767.4 Japan application no. 2003-562159 European patens: France application no. EP03704467.4 Germany application no. EP03704467.4 Great Britain application no. EP03704467.4 Italy application no. EP03704467.4 Netherlands application no. EP03704467.4 Sweden application no. EP03704467.4 Switzerland application no. EP03704467.4},
author = {Eckelt, John and Haase, Tanja and Loske, Stefan and Wolf, Bernhard Anton},
pages = {18 pages, 7 figures},
}
@article{schneider_what_2004,
title = {On what terms and why the thermodynamic properties of polymer solutions depend on chain length up to the melt},
volume = {42},
issn = {0887-6266},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000220851600004&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/Polb.20041},
abstract = {Theoretical considerations based on chain connectivity and conformational variability of polymers have led to an uncomplicated relation for the dependence of the Flory-Huggins interaction parameter (chi) on the volume fraction of the polymer (phi) and on its number of segments (N). The validity of this expression was tested extensively with vapor-pressure measurements and inverse gas chromatography (complemented by osmotic and light scattering data from the literature) for solutions of poly(dimethylsiloxane) in thermodynamically vastly different solvents such as n-octane (n-C-8), toluene (TL), and methylethylketone (MEK) over the entire range of composition for at least six different molecular masses of the polymer. The new approach is capable of modeling the measured chi (phi, N), regardless of the thermodynamic quality of the solvent, in contrast to traditional expressions, which are often restricted to good solvents but fail for bad mixtures and vice versa. At constant polymer concentration, the X values were lowest for n-C-8 (best solvent) and highest for MEK (Theta solvent); the data for TL fell between them. The influences of N depended strongly on the thermodynamic quality of the solvent and were not restricted to dilute solutions. For good solvents, chi increased with rising N. The effect was most pronounced for n-C-8, where the different curves for chi (phi) fanned out considerably. The influences of N were less distinct for TL, and for MEK they vanished at the (endothermal) theta temperature. For worse than theta conditions, the chi values of the long chains were less than that of the short ones. This change in the sign of N agreed with this concept of conformational relaxation. (C) 2004 Wiley Periodicals, Inc.},
language = {English},
number = {9},
journal = {Journal of Polymer Science Part B-Polymer Physics},
author = {Schneider, A. and Schuld, N. and Bercea, M. and Wolf, B. A.},
month = may,
year = {2004},
keywords = {polystyrene, pressure, cyclohexane, phase-separation, thermodynamics, flory-huggins interaction parameter, model, solvent quality, composition dependence, chain-length dependence, clues, conformational variability, connectivity, huggins interaction parameters, modeling of thermodynamic properties, polysiloxanes, solutions properties},
pages = {1601--1609},
}
@article{jiang_pressure_2003,
title = {Pressure effects on the thermodynamics of trans-decahydronaphthalene/polystyrene polymer solutions: {Application} of the {Sanchez}-{Lacombe} lattice fluid theory},
volume = {204},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000182265000018&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.200390038},
abstract = {The cloud-point temperatures (T-cl's) of trans-decahydronaphthalene(TD)/polystyrene (PS, (M) over bar (w) = 270 000) solutions were determined by light scattering measurements over a range of temperatures (1-16degreesC), pressures (100-900 bar), and compositions (4.2-21.6 vol.-\% polymer). The system phase separates upon cooling and T-cl was found to increase with rising pressure for constant composition. In the absence of special effects, this finding indicates positive excess volume for the mixing. Special attention was paid to the demixing temperatures as a function of pressure for different polymer solutions and the plots in the T-phi plane (where phi signifies volume fractions). The cloud-point curves of polymer solutions under different pressures were observed for different compositions, which demonstrated that pressure has a greater effect on the TD/PS solutions when far from the critical point as opposed to near the critical point. The Sanchez-Lacombe lattice fluid theory (SLLFT) was used to calculate the spinodals, the binodals, the Flory-Huggins (FH) interaction parameter, the enthalpy of mixing, and the volume changes of mixing. The calculated results show that modified PS scaling parameters can describe the thermodynamics of the TD/PS system well. Moreover the SLLFT describes the experimental results well.},
language = {English},
number = {4},
journal = {Macromolecular Chemistry and Physics},
author = {Jiang, S. C. and An, L. J. and Jiang, B. Z. and Wolf, B. A.},
month = mar,
year = {2003},
keywords = {dependence, polystyrene, phase-separation behavior, systems, phase separation, state, thermodynamics, blends, equilibria, compressibility, neutron-scattering, critical solution temperature, polymer solution, pressure effects, sanchez-lacombe lattice fluid theory, trans-decahydronaphthalene/polystyrene},
pages = {692--703},
}
@article{jiang_liquid-liquid_2003,
title = {Liquid-liquid phase behavior of toluene/polyethylene oxide/poly(ethyleneoxide-b-dimethylsiloxane) polymer-containing ternary mixtures},
volume = {5},
issn = {1463-9076},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000182602400017&action=retrieve&mode=FullRecord},
doi = {Doi 10.1039/B211559j},
abstract = {The experimental data of phase diagrams for both polyethylene oxide/poly(ethylene oxide-b-dimethylsiloxane) binary and toluene/polyethylene oxide/poly(ethylene oxide-b-dimethylsiloxane) ternary polymer-containing systems was obtained at atmosphere pressure by light scattering method. The critical points for some pre-selected compositions and the pressure effect on the phase transition behavior of ternary system were investigated by turbidity measurements. The chosen system is a mixture of ternary which is one of the very few abnormal polymer-containing systems exhibiting pressure-induced both miscibility and immiscibility. This unusual behavior is related to the toluene concentration in the mixtures. The effect of toluene on the phase transition behavior of the ternary polymer-containing mixture was traced. Such behavior can make it possible to process composite materials from incompatible polymers.},
language = {English},
number = {10},
journal = {Physical Chemistry Chemical Physics},
author = {Jiang, S. C. and An, L. J. and Jiang, B. Z. and Wolf, B. A.},
year = {2003},
keywords = {dependence, miscibility, kinetics, systems, thermodynamics, blends, equation, separation, dynamics, pressure-induced compatibility},
pages = {2066--2071},
}
@article{loske_basis_2003,
title = {Basis for the preparative fractionation of a statistical copolymer ({SAN}) with respect to either chain length or chemical composition},
volume = {36},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000183881400049&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma0343838},
abstract = {The possibilities to fractionate copolymers with respect to their chemical composition on a preparative scale by means of the establishment of liquid/liquid phase equilibria were studied for random copolymers of styrene and acrylonitrile (SAN). Experiments with solutions of SAN in toluene have shown that fractionation does in this quasi-binary system, where demixing results from marginal solvent quality, take place with respect to the chain length of the polymer only. On the other hand, if phase separation is induced by a second, chemically different polymer, one can find conditions under which fractionation with respect to composition becomes dominant. This opportunity is documented for the quasi-ternary system DMAc/SAN/polystyrene, where the solvent dimethylacetamide is completely miscible with both polymers. The theoretical reasons for the different fractionation mechanisms are discussed.},
language = {English},
number = {13},
journal = {Macromolecules},
author = {Loske, S. and Schneider, A. and Wolf, B. A.},
month = jul,
year = {2003},
keywords = {system, behavior, interfacial-tension, polymers, solvent, phase-diagrams, derivatives},
pages = {5008--5012},
}
@article{khasanova_peochcl3_2003,
title = {{PEO}/{CHCl3}. {Crystallinity} of the polymer and vapor pressure of the solvent. {Equilibrium} and nonequilibrium phenomena},
volume = {36},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000184943100050&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma034527i},
abstract = {Vapor pressures were measured for the system CHCl3/PEO 1000 (PEO stands for poly(ethylene oxide) and 1000 for M-w in kg/mol) at 25 degreesC as a function of the weight fraction w of the polymer by means of a combination of headspace sampling and gas chromatography. The establishment of thermodynamic equilibria was assisted by employing thin polymer films. The degrees of crystallinity a of the pure PEO and of the solid polymer contained in the mixtures were determined via DSC. Am analogous degree of polymer insolubility beta was calculated from the vapor pressures measured in this composition range. The experiments demonstrate that both quantities and their concentration dependence are markedly affected by the particular mode of film preparation. These nonequilibrium phenomena are discussed in terms of frozen local and temporal equilibria, where differences between alpha and beta are attributed to the occlusion of amorphous material within crystalline domains. Equilibrium information was obtained from two sources, namely from the vapor pressures in the absence of crystalline material (gas/liquid) and from the saturation concentration PEO (liquid/solid). The thermodynamic consistency of these data is demonstrated using a new approach that enables the modeling of composition dependent interaction parameters by means of two adjustable parameters only.},
language = {English},
number = {17},
journal = {Macromolecules},
author = {Khasanova, A. Y. and Wolf, B. A.},
month = aug,
year = {2003},
keywords = {poly(methyl methacrylate), melting-point depression, poly(vinylidene fluoride), conformational variability, huggins interaction parameters, adequate thermodynamic description, angle x-ray, chain connectivity, crystallization behavior, poly(ethylene oxide) blends},
pages = {6645--6652},
}
@article{stryuk_chain_2003,
title = {Chain connectivity and conformational variability of polymers: {Clues} to an adequate thermodynamic description of their solutions, 3(a) - {Modeling} of phase diagrams},
volume = {204},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000186573900004&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.200350061},
abstract = {A simple expression for the composition dependence of the Flory-Huggins interaction parameter of polymer/solvent systems reported earlier is used to model the demixing of polymer solutions into two liquid phases. To this end, the system specific parameters zeta and v of that approach are calculated as a function of temperature using the thermodynamic expressions resulting for the critical conditions on one side and from experimentally determined critical data for polymers of different molar mass on the other side. By means of data reported for the system cyclohexane/poly styrene it is demonstrated that binodal and spinodal lines are very accurately modelled at low temperatures (UCSTs) and at high temperatures (LCSTs). The parameters obtained from the demixing behavior match well with that calculated from the composition dependence of the vapor pressure at temperatures where the components are completely miscible. Information on the phase separation of the system trans-decalin/polystyrene for different molecular weights and at different elevated pressures is used to show that the approach is also apt to model pressure influences. The thus obtained zeta(T;p) and v(T;p) enable the prediction of the (endothermal) theta temperature of the system as a function of pressure in quantitative agreement with the data directly obtained from light scattering measurements with dilute solutions.},
language = {English},
number = {16},
journal = {Macromolecular Chemistry and Physics},
author = {Stryuk, S. and Wolf, B. A.},
month = nov,
year = {2003},
keywords = {temperature, phase diagrams, copolymer, cyclohexane/polystyrene, flory-huggins interaction parameters, modeling, pressure influences, trans-decalin/polystyrene},
pages = {1948--1955},
}
@article{jiang_abnormal_2003,
title = {Abnormal pressure dependence of the phase boundaries in {TL}/{PEO}/{P}({EO}-b-{DMS}) ternary mixtures},
volume = {68},
issn = {1098-0121},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000185240100036&action=retrieve&mode=FullRecord},
doi = {Artn 054110 Doi 10.1103/Physrevb.68.054110},
abstract = {The cloud-point temperatures (T-cl's) of both binary poly(ethylene oxide) (PEO)-poly(ethylene oxide-b-dimethylsiloxane) [P(EO-b-DMS)] and ternary[toluene/PEO/P(EO-b-DMS)] systems were determined by light scattering measurements at atmospheric pressure. The phase separation behavior upon cooling in the ternary system has been investigated at atmospheric pressure and under high pressure and compared to the phase behavior in the binary system. The phase transition temperatures have been obtained for all of the samples. As a result, the pressure induces compatibility in the binary mixtures, but for the ternary system, pressure not only can induce mixing but also can induce phase separation.},
language = {English},
number = {5},
journal = {Physical Review B},
author = {Jiang, S. C. and Jiang, W. and Wolf, B. A. and An, L. J. and Jiang, B. Z.},
month = aug,
year = {2003},
keywords = {polystyrene, diblock copolymers, temperature, polymer blends, block-copolymer melts, compressibility, neutron-scattering, induced compatibility, solubility limits, true cosolvency},
}
@article{eckelt_large_2004,
title = {Large scale fractionation of macromolecules},
volume = {289},
issn = {1438-7492},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000221635800002&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/mame.200300374},
abstract = {Access to sufficiently large amounts of material with adequate molecular and chemical uniformity from polydisperse natural products or synthetic materials has been a long-standing challenge to polymer scientists. We have developed a broadly applicable preparative fractionation method consisting of a special kind of continuous extraction removing the easier soluble components from the initial product. It is rendered possible by the use of spinning nozzles through which a concentrated polymer solution is pressed into a liquid of tailored thermodynamic quality. The initially produced jets of the source phase disintegrate rapidly into minute droplets of typically 50 mum diameter. This efficient subdivision provides the large surfaces and short routs of transport required for successful fractionation. Thus the pronounced kinetic hindrances resulting from the high viscosities of reasonable concentrated polymer solutions can be overcome. We portray the principal features of continuous spin fractionation and present two examples of practical importance.},
language = {English},
number = {5},
journal = {Macromolecular Materials and Engineering},
author = {Eckelt, J. and Haase, T. and Loske, S. and Wolf, B. A.},
month = may,
year = {2004},
keywords = {phase separation, continuous polymer fractionation, hydroxyethyl starch, continuous extraction, fractionation of polymers, high performance polymers, molecular weight distribution/molecular mass distribution},
pages = {393--399},
}
@article{stryuk_solutions_2005,
title = {Solutions of cellulose in {DMAc} + {LiCl}: migration of the solute in an electrical field},
volume = {12},
issn = {0969-0239},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000227077700004&action=retrieve&mode=FullRecord},
doi = {DOI 10.1007/s10570-004-0213-0},
abstract = {For solutions of cellulose ( Solucell, M-w = 230 kg mol(-1)) in the mixed solvent DMAc ( N, N- dimethylacetamide) + LiCl, it is demonstrated by means of an electrolysis cell, subdivided into six compartments, that cellulose migrates to the anode. This observation is interpreted in terms of a field-induced opening of associations between the  DMAc Li+ complex and the [ cellulose] Cl- complex. This understanding is corroborated by the observed changes in the positions of the menisci in the electrode compartments of the electrolysis cell. Contrary to expectations, the rate of cellulose transport does not depend on its molar mass, at least under the present conditions.},
language = {English},
number = {2},
journal = {Cellulose},
author = {Stryuk, S. and Eckelt, J. and Wolf, B. A.},
month = apr,
year = {2005},
keywords = {fractionation, solvent, cellulose, n,n-dimethylacetamide, unsubstituted cellulose, dissolution, dissolution mechanism, dmac plus licl, dmac/licl, electrolysis, licl},
pages = {145--149},
}
@article{shi_evolution_2004,
title = {Evolution of the interfacial tension between polydisperse "immiscible" polymers in the absence and in the presence of a compatibilizer},
volume = {37},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000189091800054&action=retrieve&mode=FullRecord},
doi = {10.1021/ma035616y},
abstract = {The interfacial tension sigma between two polyisobutylenes (PIB) of dissimilar polydispersity and two polydisperse samples of poly(dimethylsiloxane) (PDMS) was measured as a function of time by means of a pendent drop apparatus at different temperatures ranging from 30 to 110 degreesC. In addition to three of the four possible binary blends, the time evolution of sigma was also determined for one ternary system, where the PIB phase contained 0.03 wt \% of a diblock copolymer poly(isobutylene-b-dimethylsiloxane). The pronounced decrease of sigma with advancing time, observed in all cases, is attributed to the migration of the interfacially active lower molecular weight components of the homopolymers and of the compatibilizer into the interphase. Several days are normally required until a becomes constant. These time independent values are not considered as equilibrium data, but accredited to stationary states. A kinetic model is established for sigma(t), which enables a detailed investigation of the rates of transport of the different migrating species of average molar mass of M. Its application to the present data discloses that the characteristic times tau of their diffusion depend on M-d, where the estimated d values vary between 2.9 and 5.1. The modeled dependence of tau on the viscosities of the coexisting phases suggests that the activation energies for tau should be found somewhere between the activation energies for the viscous flow of these bulk phases. The experimental observations corroborate this postulate.},
language = {English},
number = {4},
journal = {Macromolecules},
author = {Shi, T. F. and Ziegler, V. E. and Welge, I. C. and An, L. J. and Wolf, B. A.},
month = feb,
year = {2004},
keywords = {continuous fractionation, pib, temperature, molecular-weight, profile},
pages = {1591--1599},
}
@article{jiang_temperature_2004,
title = {Temperature and pressure dependence of phase separation of trans-decahydronaphthalene/polystyrene solution},
volume = {298},
issn = {0301-0104},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000189216600004&action=retrieve&mode=FullRecord},
doi = {DOI 10.1016/j.chemphys.2003.11.002},
abstract = {The cloud-point temperatures (T-c1's) of ti-ans-decahydronaphthalene (TD)/polystyrene (PS, M-w = 270 kg/mol) solutions were determined by fight scattering measurements over a range of temperatures (1-16 degreesC), pressures (100-900 bar), and compositions (4.2-21.6 vol\% polymer). The system phase separates upon cooling and the T-c1 was found to increase with the rising pressure for the constant composition. In the absence of special effects this finding indicates positive excess volumes. The special attention was paid to the demixing temperatures as a function of the pressure for the different polymer solutions and the plots in the T-volume fraction plane and P-volume fraction plane. The cloud-point curves of polymer solutions under changing pressures were observed for different compositions, demonstrates that the TD/PS system exhibits UCST (phase separation upon cooling) behavior. With this data the phase diagrams under pressure were calculated applying the Sanchez-Lacombe (SL) lattice fluid theory. Furthermore, the cause of phase separation, i.e., the influence of Flory-Huggins (FH) interaction parameter under pressure was investigated. The predictions of the SL theory concerning the FH interaction parameter and the influence of pressure on miscibility are investigated. The LCSP (phase separation upon increasing pressure) and UCST behavior were predicated by extrapolating the pressure to negative region on pressure-composition plane for TD/PS polymer solutions. (C) 2003 Elsevier B.V. All rights reserved.},
language = {English},
number = {1-3},
journal = {Chemical Physics},
author = {Jiang, S. C. and An, L. J. and Jiang, B. Z. and Wolf, B. A.},
month = mar,
year = {2004},
keywords = {polystyrene, polymer-solutions, behavior, thermodynamics, blends, neutron-scattering, solubility limits, true cosolvency, field lattice equations, fluid theory, negative pressure, poly(decyl methacrylate), pressure effect, td/ps polymer solution},
pages = {37--45},
}
@article{schnell_liquidliquid_2004,
title = {Liquid/liquid demixing in the system n-hexane/narrowly distributed linear polyethylene},
volume = {43},
issn = {0888-5885},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000221586100028&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ie034302w},
abstract = {Demixing conditions were measured visually for solutions of three narrowly distributed polyethylene samples (M ranging from 6.5 to 380 kg/mol) in n-hexane up to 500 K and 150 bar. This information yields the critical line for infinite molar mass; i.e., it specifies the pT area within which one is safe from phase separation irrespective of the molar mass of the polymer and of the composition of the mixture. The experimental findings are in good qualitative agreement with the predictions of the Sanchez-Lacombe theory applied without any adjustable parameters. The influences of molar masses are, however, underestimated, and the resulting critical compositions are too small. For a more quantitative description, the observed phase behavior of the system was modeled by means of the Flory-Huggins theory, employing a new expression for the concentration dependence of the interaction parameter, which is based on chain connectivity and conformational relaxation. With this procedure, the required system-specific parameters are obtained from the critical conditions measured for different M values of the polymer. Despite the fact that only the data for the two higher molecular weight samples could be used for that purpose, the calculated binodals and spinodals appear reasonable.},
language = {English},
number = {11},
journal = {Industrial \& Engineering Chemistry Research},
author = {Schnell, M. and Stryuk, S. and Wolf, B. A.},
month = may,
year = {2004},
keywords = {polymer-solutions, conformational variability, adequate thermodynamic description, chain connectivity, fluid theory equation, hexane polyethylene, liquid-phase-separation, sanchez-lacombe model, solvent systems, vapor-pressure},
pages = {2852--2859},
}
@article{ziegler_interfacial_2004,
title = {Interfacial tensions from drop retraction versus pendant drop data and polydispersity effects},
volume = {20},
issn = {0743-7463},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000224039000042&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/La049288m},
abstract = {Interfacial tensions a were measured by means of both methods for the following polymer pair: polyisobutylene (PIB 3) plus poly(dimethylsiloxane) (PDMS 152) and poly(dimethyl-co-methylphenylsiloxane) (CoP26*) plus PDMS 48. The numbers after the abbreviation state the molar masses in kilograms; the homopolymers exhibit polydispersities on the order of 2. The reliability of the method of drop retraction is backed up by systematic measurements, which demonstrate that it is possible to study the time evolution of a. Because of the free choice of the phases (drop or matrix) and the possibility to vary the overall composition of the system in a wide range, drop retraction yields more information than the pendant drop method. For the present systems both types of experiments yield identical results for the droplets of higher density. Experiments with the inverse blends and at higher volume fractions of the disperse phase demonstrate that the polydispersity of the components plays an important role. In the case of the system PIB 3/PDMS 152 the steady-state interfacial tension at 25 degreesC is 2.25 mN m(-1) if the drop consists of PDMS, but only 1.3 mN m(-1) if it consists of PIB. Furthermore, the time-independent a values are attained much more rapidly in the latter case.},
language = {English},
number = {20},
journal = {Langmuir},
author = {Ziegler, V. E. and Wolf, B. A.},
month = sep,
year = {2004},
keywords = {flow, polymers, molecular-weight, profile, deformation, fluid},
pages = {8688--8692},
}
@article{jiang_thermodynamics_2003,
title = {Thermodynamics of phase behavior in {PEO}/{P}({EO}-b-{DMS}) homopolymer and block co-oligomer mixtures under pressure},
volume = {204},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000187619000011&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.200350077},
abstract = {The cloud-point temperatures (T-cl's) of poly(ethylene oxide) (PEO) and poly(ethylene oxide)-block-polydimethylsiloxane (P(EO-b-DMS)) homopolymer and block-oligomer mixtures were determined by turbidity measurements over a range of temperatures (105 to 130degrees), pressures (1 to 800 bar), and compositions (10-40 wt.-\% PEO). The system phase separates upon cooling and T-cl was found to decrease with an increase in pressure for a constant composition. In the absence of special effects, this finding indicates negative excess volumes. Special attention was paid to the demixing temperatures as a function of the pressure for the different polymer mixtures and the plots in the T-phi plane (where phi signifies volume fractions). The cloud-point curves of the polymer mixture under pressures were observed for different compositions. The Sanchez-Lacombe (SL) lattice fluid theory was used to calculate the spinodals, the binodals, the Flory-Huggins (FH) interaction parameter, the enthalphy of mixing, and the volume changes of mixing. The calculated results show that modified P(EO-b-DMS) scaling parameters with the new combining rules can describe the thermodynamics of the PEO/P(EO-b-DMS) system well with the SL theory.},
language = {English},
number = {18},
journal = {Macromolecular Chemistry and Physics},
author = {Jiang, S. C. and An, L. J. and Jiang, B. Z. and Wolf, B. A.},
month = dec,
year = {2003},
keywords = {dependence, polystyrene, temperature, polymer blends, state, thermodynamics, neutron-scattering, phase behavior, pressure effects, sanchez-lacombe lattice fluid theory, induced compatibility, field lattice equations, fluid theory, poly(ethylene oxide)/poly(ethylene oxide)-block-polydimethylsiloxane mixture, separation behavior},
pages = {2265--2273},
}
@article{eckelt_membranes_2005,
title = {Membranes directly prepared from solutions of unsubstituted cellulose},
volume = {206},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000226696300005&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.200400366},
abstract = {Starting from 5 wt.-\% solutions of a prehydrolysis kraft pulp ((M) over bar (n) = 135 kg (.) mol(-1)) in the mixed solvent (dimethylacetamide + 7 wt.-\% LiCl) we have prepared cellulose membranes on different supports according to the phase inversion process using above all Acetone (AC) and 2-propanol as precipitants. In this context we have studied the phase behavior of the quasiternary system (DMAc+LiCl)/AC/cellulose. The obtained membranes are mechanically stable and in their mechanical and separation properties on the whole comparable to membranes consisting of regenerated cellulose. With respect to gas separation the ideal selectivity of CO2 in combination with N-2 and O-2 turns out to be opposite for the present membranes as compared with that consisting of regenerated cellulose. Ultrafiltration experiments performed with aqueous solutions of polyethylene oxide differing widely in their molar mass resulted in cut-off molecular weights ranging from 3 to 9 kg/mol.},
language = {English},
number = {2},
journal = {Macromolecular Chemistry and Physics},
author = {Eckelt, J. and Wolf, B. A.},
month = jan,
year = {2005},
keywords = {polymer, fractionation, n,n-dimethylacetamide, unsubstituted cellulose, dmac plus licl, cuoxam, gas permeation, membranes, ultrafiltration},
pages = {227--232},
}
@article{schnell_isobornyl_2004,
title = {Isobornyl methacrylate as a reactive solvent of polyethylene},
volume = {289},
issn = {1438-7492},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000222908600005&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/mame.200400061},
abstract = {Solutions containing 15 wt.-\% of a low-molarmass polyethylene (PE) in isobomyl methacrylate (IBoMA), containing 0, 5 or 10 wt.-\% of 1,4 butanediol dimethacrylate (BDDMA) as crosslinker, were polymerized using either benzoyl peroxide (bPO), at 80degreesC, or dicumyl peroxide (DCPO), with a thermal cycle attaining 150degreesC, as initiators. Phase separation of an amorphous PE-rich phase took place when carrying out the reaction at temperatures higher than the PE melting temperature. Partial crystallization of PE was observed when cooling to room temperature. Depending on the initial amount of BDDMA, the fraction of PE that was phase separated varied between 57 and 66\% of the initial amount, with crystalline fractions in the range of 15 to 42\%. The use of IBoMA as a reactive solvent of PE has two main advantages over other reactive solvents reported in the literature: a) it has a very low vapor pressure, and b) its freeradical polymerization gives a polymer with a relatively high glass transition temperature.},
language = {English},
number = {7},
journal = {Macromolecular Materials and Engineering},
author = {Schnell, M. and Borrajo, J. and William, R. J. J. and Wolf, B. A.},
month = jul,
year = {2004},
keywords = {behavior, miscibility, systems, phase separation, blends, copolymers, butyl methacrylate, degradation, interpenetrating-like networks, phase segregation, polyethylene (pe), polymerization, polystyrene-polyethylene, reactive processing},
pages = {642--647},
}
@article{wolf_polymer-optimierung_2004,
title = {{POLYMER}-{OPTIMIERUNG} {FÜR} {MEDIZIN} {UND} {TECHNIK}},
number = {2},
journal = {CHEMIE report},
author = {Wolf, Bernhard Anton},
year = {2004},
pages = {36--39},
}
@article{wolf_praparative_2004,
title = {Präparative {Fraktionierung} von {Polymeren} für den optimierten {Einsatz} in {Technik} und {Medizin}},
journal = {Jahresbericht 2003 der Innovationsstiftung des Landes Rheinland-Pfalz},
author = {Wolf, Bernhard Anton},
year = {2004},
}
@article{wolf_spinnfraktionierung_2004,
title = {Spinnfraktionierung von {Polymeren}},
volume = {52},
journal = {Nachrichten aus der Chemie, Zeitschrift der GEellschaft Deutscher Chemiker},
author = {Wolf, Bernhard Anton},
year = {2004},
pages = {783},
}
@article{bumbu_investigation_2004,
title = {Investigation of the interpolymer complex between hydroxypropyl cellulose and maleic acid-styrene copolymer, 1 - {Dilute} solutions studies},
volume = {205},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000224239400007&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.200400253},
abstract = {The hydrogen bonding-interpolymer association of hydroxypropyl cellulose (HPC) with maleic acid-styrene (MAc-S) copolymer has been investigated in dilute aqueous solution by viscometry, turbidimetry and potentiometry. At a mixing ratio between MAc-S and HPC of 10:90, the solution exhibits a phase separation upon heating, while for other mixing ratio no phase separation could be detected. The stability of the interpolymer complex (IPC) increases as the temperature rises. The stoichiometry of the IPC, in mole units, was estimated as being MAc-S:HPC = 5:2. The thermodynamic functions (enthalpy and entropy) of the complexation process have been determined.},
language = {English},
number = {14},
journal = {Macromolecular Chemistry and Physics},
author = {Bumbu, G. G. and Vasile, C. and Eckelt, J. and Wolf, B. A.},
month = sep,
year = {2004},
keywords = {thermodynamics, polymers, blends, poly(ethylene oxide), phase-behavior, phase behavior, anhydride, aqueous-solutions, association, hydroxypropyl cellulose, interpolymer complex, maleic acid-styrene copolymer, poly(acrylic acid), polyacrylic-acid, polysaccharides},
pages = {1869--1876},
}
@article{wolf_reasons_2005,
title = {On the reasons for an anomalous demixing behavior of polymer solutions},
volume = {38},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000227085400049&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma047919d},
abstract = {Some extraordinary solutions of polymers in single solvents exhibit two liquid/liquid critical points, one within the usual composition range and a second one in the range of moderate to high polymer concentration. This particularity was studied theoretically by means of a recently established approach, which accounts explicitly for chain connectivity and for the ability of polymer molecules to respond to changes in their environment by conformational rearrangements. On the basis of model calculations, it is shown that the anomalous demixing behavior, i.e., the emergence of a second critical point, is bound to the necessary but not sufficient condition that a thermodynamically very unfavorable contact formation between polymer segments and solvent molecules (at fixed conformation of the components) is associated with an extraordinarily favorable conformational response. Possibilities to forecast whether certain systems behave normal or in an anomalous manner are discussed.},
language = {English},
number = {4},
journal = {Macromolecules},
author = {Wolf, B. A.},
month = feb,
year = {2005},
keywords = {phase-diagrams, derivatives, gibbs energy, conformational variability, huggins interaction parameters, adequate thermodynamic description, chain connectivity, high molar masses, polydisperse polymers, zero critical concentrations},
pages = {1378--1384},
}
@article{stryuk_liquidgas_2005,
title = {Liquid/gas and liquid/liquid phase behavior of n-butane/1,4-polybutadiene versus n-butane/1,2-polybutadiene},
volume = {38},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000226764500024&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma0479058},
abstract = {Solutions of 1,4-polybutadiene (1,4-PB, 98\% cis) and of 1,2-polybutadiene (1,2-PB) in n-butane (n-C-4) were studied with respect to their vapor pressure and to their demixing into two liquid phases under isochoric conditions within the temperature range from 25 to 75 degreesC. 1,2-PB mixes homogeneously with n-C-4 at any ratio, in contrast to 1,4-PB, which exhibits a miscibility gap extending from practically pure solvent to approximately 40 wt \% polymer. Corresponding to these solubility differences, the vapor pressures for the system n-C-4/1,4-PB are considerably higher than for n-C-4/1,2-PB at the same concentration and temperature. The experimental results are modeled accurately and consistently by means of a modified Flory-Huggins approach accounting explicitly for chain connectivity and conformational variability of the polymers. The vapor pressures calculated by means of the Sanchez-Lacombe theory agree very well with the experimental data for both systems; this approach fails, however, in the case of the liquid/liquid phase equilibria because it predicts similar miscibility gaps for both polymers. The modified Flory-Huggins approach explains the fundamentally different solubility of 1,2-PB and 1,4-PB in terms of pronounced dissimilarities in their conformational response to dilution, which is in the case of 1,4-PB strongly impeded by the double bonds of the main chain.},
language = {English},
number = {3},
journal = {Macromolecules},
author = {Stryuk, S. and Wolf, B. A.},
month = feb,
year = {2005},
keywords = {dependence, polymer-solutions, state, equation, clues, conformational variability, huggins interaction parameters, adequate thermodynamic description, chain connectivity},
pages = {812--817},
}
@article{eckelt_large_2006,
title = {Large scale fractionation of pullulan and dextran},
volume = {63},
issn = {0144-8617},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000235358200006&action=retrieve&mode=FullRecord},
doi = {DOI 10.1016/j.carbpol..2005.08.026},
abstract = {A recently developed large scale fractionation technique named continuous spin fractionation (CSF) was applied to fractionate pullulan and dextran. 450 g of pullulan with a broad molecular weight distribution were fractionated using water as solvent and acetone as precipitant. In this study, we have in five CSF runs prepared three fractions with apparent (M) over bar (double dagger)(W) values ranging from 17.6 to 413 kg mol(-1). Seventy grams of dextran were fractionated with a mixed solvent of water plus methanol. Five fractionation steps resulted in four samples with R, values between 4.36 and 18.2 kg mol(-1). (c) 2005 Elsevier Ltd. All rights reserved.},
language = {English},
number = {2},
journal = {Carbohydrate Polymers},
author = {Eckelt, J. and Sugaya, R. and Wolf, B. A.},
month = feb,
year = {2006},
keywords = {continuous polymer fractionation, phase-diagrams, fractionation of polymers, dextran, macromolecules, molecular weight distribution/molar mass distribution, pullulan},
pages = {205--209},
}
@article{ziegler_bimodal_2005,
title = {Bimodal drop size distributions during the early stages of shear induced coalescence},
volume = {46},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000232642300006&action=retrieve&mode=FullRecord},
doi = {DOI 10.1016/j.polymer.2005.07.055},
abstract = {Drop sizes and drop size distributions were determined by means of an optical shear cell in combination with an optical microscope for the systems polyisobutylene/poly(dimethylsiloxane) [I] and poly(dimethyl-co-methylphenylsiloxane)/poly(dimethylsiloxane) [II] at low concentrations of the suspended phases and at different constant shear rates ranging from 10 to 0.5 s(-1). After pre-shearing the two-phase mixtures [I: 50 s(-1); II: 100 s(-1)] for the purpose of producing small drop radii, the shear rate was abruptly reduced to the preselected value and coalescence was studied as a function of time. In all cases one approaches dead end drop radii, i.e. breakup is absent. The drop size distributions are for sufficiently long shearing always unimodal, but within the early stages of coalescence they are in some cases bimodal; the shape of the different peaks is invariably Gaussian. The results are discussed by means of Elmendorp diagrams and interpreted in terms of collision frequencies and collision efficiencies. (c) 2005 Elsevier Ltd. All rights reserved.},
language = {English},
number = {22},
journal = {Polymer},
author = {Ziegler, V. E. and Wolf, B. A.},
month = oct,
year = {2005},
keywords = {flow, viscosity, polymer blends, immiscible polymer blends, morphology, deformation, fluid, homopolymer/copolymer blend, hysteresis, model blends, particle motions, shear induced coalescence, suspensions},
pages = {9265--9273},
}
@article{ziegler_role_2005,
title = {On the role of drop break up for coalescence processes and morphology development in polymer blends under shear},
volume = {38},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000230023400064&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma050504n},
abstract = {Drop sizes and drop-size distributions were determined as a function of time at constant shear rates,, by means of an optical shear cell in combination with an optical light microscope after preshearing the samples at high. The systems under investigation were PIB 3/PDMS 152 (PIB: polyisobutylene, PDMS: poly(dimethylsiloxane), numbers: average molar masses in kg/mol) and COP 26*/PDMS 48 (COP: poly(dimethyl-co-methylphenylsiloxane), asterisk: apparent molar mass); all measurements refer to 25 degrees C. Systems and conditions were chosen such that shear rates in the vicinity of the intersection of the coalescence and the break up curves become experimentally accessible. Under these conditions, it is important to evaluate the different processes not only in terms of average drop radii but also in terms of their distribution. Such an analysis demonstrates that there exists a kind of transition from the typical behavior at low shear rates (far below the intersection, only coalescence, approach of dead-end drop radii) to that at high shear rates (far above the intersection, simultaneous coalescence and break up, approach of stationary drop radii). Within the entire transition regime between these two ordinary types of behavior, some drops are larger and others smaller than the corresponding break up radius, and the fraction of larger drops increases from zero to unity as one raises the shear rate. In some cases, one observes bimodal distributions of drop size where the ratio of the volumes of the two kinds of drops is either four or eight.},
language = {English},
number = {13},
journal = {Macromolecules},
author = {Ziegler, V. E. and Wolf, B. A.},
month = jun,
year = {2005},
keywords = {flow, viscosity, interfacial-tension, fluid, hysteresis, model blends, evolution, fields, retraction},
pages = {5826--5833},
}
@incollection{hagenaars_advanced_2005,
series = {{ACS} {Symposium} {Series} 898},
title = {Advanced {Solution} {Characterization} of {Polycarbonate} {Materials} across the {Molecular} {Weight} {Distribution}},
volume = {ACS Symposium Series 898},
number = {898},
booktitle = {Advances in {Polycarbonates}},
publisher = {Oxford University Press},
author = {Hagenaars, Arno and Wolf, Bernhard Anton and Bailly, Christian},
editor = {Korn, Michael R. and Brunelle, Daniel J.},
year = {2005},
pages = {180--199},
}
@article{bumbu_interpolymer_2005,
title = {Interpolymer complex between hydroxypropyl cellulose and maleic acid-styrene copolymer: {Phase} behavior of semi-dilute solutions},
volume = {5},
issn = {1616-5187},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000233002900003&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/mabi.200500070},
abstract = {The phase behavior of a water/hydroxypropyl cellulose/maleic acid-styrene copolymer (H(2)O/HPC/MAc-S) system was investigated in the semi-dilute range by turbidimetry, rheology, and optical microscopy. The two polymers under investigation form interpolymer complexes via hydrogen bonding. In the case of a total polymer concentration of c(pol) = 5 mg(.)mL(-1) a second phase segregates upon heating the homogeneous ternary system. By applying a constant shear rate (gamma = 50 s(-1)) the phase separation temperature of the system is 10 - 15 degrees C lower than for an unsheared one. For c(pol) = 10 mg(.)mL(-1) phase separation has already occurred at room temperature when the two binary polymer solutions are mixed. The distribution of the partners among the coexisting phases was examined by FT-IR spectroscopy. The stoichiometry of the interpolymeric complex (IPC) was estimated to be HPC/MAc-S = 40:60 (w/w) independent of c(pol).},
language = {English},
number = {10},
journal = {Macromolecular Bioscience},
author = {Bumbu, G. G. and Eckelt, J. and Wolf, B. A. and Vasile, C.},
month = oct,
year = {2005},
keywords = {polymer blends, rheology, compatibility, molecular-weight, separation, poly(ethylene oxide), phase behavior, anhydride, hydroxypropyl cellulose, interpolymer complex, maleic acid-styrene copolymer, poly(acrylic acid), polysaccharides, hydrogen bonding, medicine release, thermal-behavior},
pages = {936--944},
}
@article{wolf_polymer-polymer_2006,
title = {Polymer-polymer interaction: {Consistent} modeling in terms of chain connectivity and conformational response},
volume = {207},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000234641100008&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.200500417},
abstract = {An approach developed for the modeling of polymer solutions is extended to polymer blends. It accounts explicitly for the fact that the segments of a given macromolecule cannot spread out over the entire volume of the system (chain connectivity) and that the space a polymer molecule occupies may change after contact formation between the components of a mixture (conformational response). The validity of the equation obtained for the Flory-Huggins interaction parameter between polymers is tested by means of critical data published for the system PVME/PS. The measured phase diagrams can be modeled equally well by two limiting assumptions concerning the temperature dependence of the conformational response. However, using these two different sets of parameters to calculate the phase behavior for high molar masses of both polymers, leads to fundamental differences. One of them yields double critical points and predicts well defined critical compositions in the limit of infinite molar masses of both polymers, in contrast to the original Flory-Huggins theory. The physical meaning of the different parameters is analyzed and the composition and temperature dependencies of the Flory-Huggins interaction parameter resulting from the present modeling are compared with corresponding data reported in the literature.},
language = {English},
number = {1},
journal = {Macromolecular Chemistry and Physics},
author = {Wolf, B. A.},
month = jan,
year = {2006},
keywords = {dependence, polyvinyl methyl-ether), angle neutron-scattering, polymer blends, interaction parameters, separation, phase diagrams, clues, adequate thermodynamic description, flory-huggins interaction parameters, modeling, phase-diagram, poly(vinyl methyl ether)/polystyrene, polystyrene poly(vinylmethylether) blends, variability},
pages = {65--74},
}
@article{antonov_calorimetric_2005,
title = {Calorimetric and structural investigation of the interaction between bovine serum albumin and high molecular weight dextran in water},
volume = {6},
issn = {1525-7797},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000233392100014&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Bm050279h},
abstract = {This work studies specific interactions between a small globular protein and a highly flexible, branched polysaccharide using differential scanning calorimetry (DSC), circular dichroism (CD), fluorescence, and turbidimetry measurements. It uses the system water/bovine serum albumin (BSA)/dextran (D 2000) as a model. Dextran molecules are able to form interpolymeric complexes with BSA in water at both low and high temperatures if the polysaccharide is in excess and if the protein exists in its associated state. It leads to a partial destabilization of the secondary and tertiary structures of the protein and an additional exposure of the hydrophobic tryptophan residues to the surface of globule. If the total concentration of biopolymers in the mixture is high enough, the stability of the protein molecules with respect to unfolding and thermoaggregation is significantly decreased as a result of an increase in the protein hydrophobicity.},
language = {English},
number = {6},
journal = {Biomacromolecules},
author = {Antonov, Y. A. and Wolf, B. A.},
month = dec,
year = {2005},
keywords = {aqueous polymer systems, charged polyelectrolytes, circular-dichroism, differential scanning calorimetry, ionic-strength, irreversible thermal-denaturation, ligand-binding, protein, species-differences, thermodynamic compatibility},
pages = {2980--2989},
}
@article{ziegler_morphology_2005,
title = {Morphology of {PEO}/{PDMS} blends during shear: {Coexistence} of two droplet/matrix structures and additive effects},
volume = {46},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000233733700028&action=retrieve&mode=FullRecord},
doi = {DOI 10.1016/j.polymer.2005.10.017},
abstract = {The morphologies of blends of polyethyleneoxide (PEO 37) and poly(dimethylsiloxane)s (PDSM), with viscosity ratios, of approximately one (PDMS 230) or 2.8 (PDMS 314, being the component of higher viscosity) and interfacial tensions on the order of 10 mN/m, were investigated at 70 degrees C as a function of shear rate (up to 10 s(-1)) and of time. For the system PEO 37/PDMS 230 we have also studied the influence of the compatibilizer dimethyl-ethyleneoxide-copolymer (PDMS-co-PEO), which is only reasonably soluble in PEO. To investigate the morphologies we have used an optical shear cell in combination with a light microscope. The most important observation consists in the formation of two coexisting droplet/matrix structures for volume fractions of PDMS ranging from 0.4 to 0.6 for both lambda values;, the presence of the copolymer extends this re-ion to 0.7. In the case of lambda approximate to 1 the average droplet radii are within experimental error independent of composition and morphology; for 2.8 they depend on the matrix phase in which they are contained and do again not vary with composition. The reduction in drop size caused by the copolymer is markedly larger if PEO forms the matrix. The present morphological observations suggest that the two coexisting droplet/matrix phases develop Out of a single droplet/matrix structure via coalescence processes. (c) 2005 Elsevier Ltd. All rights reserved.},
language = {English},
number = {25},
journal = {Polymer},
author = {Ziegler, V. E. and Wolf, B. A.},
month = nov,
year = {2005},
keywords = {flow, polymer blends, immiscible polymer blends, model, fluid, evolution, fields, continuity, drop, induced coalescence, morphology under shears, phase inversion},
pages = {11396--11406},
}
@article{bercea_vitrification_2006,
title = {Vitrification of polymer solutions as a function of solvent quality, analyzed via vapor pressures},
volume = {124},
issn = {0021-9606},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000237321700041&action=retrieve&mode=FullRecord},
doi = {Artn 174902 Doi 10.1063/1.2193153},
abstract = {Vapor pressures (headspace sampling in combination with gas chromatography) and glass transition temperatures [differential scanning calorimetry (DSC)] have been measured for solutions of polystyrene (PS) in either toluene (TL) (10-70 degrees C) or cyclohexane (CH) (32-60 degrees C) from moderately concentrated solutions up to the pure polymer. As long as the mixtures are liquid, the vapor pressure of TL (good solvent) is considerably lower than that of CH (theta solvent) under other identical conditions. These differences vanish upon the vitrification of the solutions. For TL the isothermal liquid-solid transition induced by an increase of polymer concentration takes place within a finite composition interval at constant vapor pressure; with CH this phenomenon is either absent or too insignificant to be detected. For PS solutions in TL the DSC traces look as usual, whereas these curves may become bimodal for solutions in CH. The implications of the vitrification of the polymer solutions for the determination of Flory-Huggins interaction parameters from vapor pressure data are discussed. A comparison of the results for TL/PS with recently published data on the same system demonstrates that the experimental method employed for the determination of vapor pressures plays an important role at high polymer concentrations and low temperatures.},
language = {English},
number = {17},
journal = {Journal of Chemical Physics},
author = {Bercea, M. and Wolf, B. A.},
month = may,
year = {2006},
keywords = {dependence, polystyrene, gas-chromatography, clues, conformational variability, huggins interaction parameters, adequate thermodynamic description, chain connectivity, glassy-polymers, sorption},
}
@article{antonov_phase_2006,
title = {Phase {Behavior} of aqueous solutions of bovine serum albumin in the presence of dextran, at rest, and under shear},
volume = {7},
issn = {1525-7797},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000237593600024&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Bm050899i},
abstract = {The demixing conditions for aqueous solutions of bovine serum albumin (BSA, fraction V) and for joint solutions of BSA plus dextran (DEX, M-w = 2000 kg/mol) were determined by turbidimetric measurements as a function of composition, temperature, and shear rate. Aqueous solutions of BSA phase separate upon heating. Within the region of BSA concentrations between 0.05 and 32 wt \%, the demixing temperature, T-1, falls from ca. 65 degrees C to an almost constant value of 45 degrees C. Adding DEX to the BSA solutions reduces the homogeneous region of the mixture drastically where the amount of DEX required to lower T1 to 25 degrees C decreases rapidly as the concentration of BSA is raised. Experiments concerning the influences of shear have been performed for the ternary system up to 500 s(-1). They demonstrate that the content of dextran determines the sign of the effect. At low DEX concentrations, the mechanical field favors the homogeneous state (shear-induced mixing), whereas the opposite effect (shear-induced demixing) is observed at high DEX concentrations. Possible reasons for this observation are discussed.},
language = {English},
number = {5},
journal = {Biomacromolecules},
author = {Antonov, Y. A. and Wolf, B. A.},
month = may,
year = {2006},
keywords = {systems, blends, diagrams, molecular-weight, separation, copolymers, common solvent, highly incompatible polymers, mechanism, protein interactions},
pages = {1562--1567},
}
@article{xiong_continuous_2006,
title = {Continuous spin fractionation and characterization by size-exclusion chromatography for styrene-butadiene block copolymers},
volume = {1110},
issn = {0021-9673},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000236439000007&action=retrieve&mode=FullRecord},
doi = {DOI 10.1016/j.chroma.2006.01.063},
abstract = {Linear and star-shaped styrene-butadiene block copolymers synthesized by anionic polymerization of butadiene and styrene were fractionated by applying a newly developed large-scale fractionation technique, named continuous spin fractionation (CSF). Their molecular weight and polydispersity index (d= M-w/M-n) were measured with size-exclusion chromatography and static light scattering. For the linear triblock copolymer a fractionation via temperature variation turned out to be better suited than the usual isothermal procedure. The star-shaped polymer with the d value of 1.33 was fractionated in two CSF steps to get the targeted sample, which has a considerably more uniform structure and a narrower molecular weight distribution (d= 1.11). The corresponding starting linear diblock copolymer was fractionated in one step reducing d from 1.68 to 1.17. With one set of simple laboratory equipment, I kg polymer can be fractionated per day. Utilizing CSF, for the first time, we fractionated successfully the block copolymers. (c) 2006 Elsevier B.V. All rights reserved.},
language = {English},
number = {1-2},
journal = {Journal of Chromatography A},
author = {Xiong, X. P. and Eckelt, J. and Wolf, B. A. and Zhang, Z. J. and Zhang, L.},
month = mar,
year = {2006},
keywords = {polymer-solutions, diblock copolymers, block copolymer, solvent, light-scattering, separation, size-exclusion chromatography, molecular weight distribution, 4-arm star polystyrene, continuous spin fractionation, dilute-solution, large-scale fractionation, phase fluctuation chromatography, shape},
pages = {53--60},
}
@article{sugaya_thermal_2006,
title = {Thermal diffusion of dextran in aqueous solutions in the absence and the presence of urea},
volume = {7},
issn = {1525-7797},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000235538600006&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Bm050545r},
abstract = {The Ludwig-Soret effect was studied for aqueous solutions of dextran in the temperature range 15 {\textless} T {\textless} 55 degrees C taking into account the effect of the addition of urea. In the absence of urea, the Soret coefficient S-T changes sign; it is positive for T {\textgreater} 45.0 degrees C but negative for T {\textless} 45.0 degrees C. The positive sign of ST means that the dextran molecules migrate toward the cold side of the fluid; this behavior is typical for polymer solutions, whereas a negative sign indicates the macromolecules move toward the hot side. The addition of urea to the aqueous solution of dextran rises ST and reduces the inversion temperature. For 2 M urea the change in the sign of S-T is observed at T = 29.7 degrees C and beyond that value S-T is always positive in the studied temperature range. To rationalize these observations, it is assumed that the addition of urea leads to an opening of hydrogen bonds similar to that induced by an increase in temperature.},
language = {English},
number = {2},
journal = {Biomacromolecules},
author = {Sugaya, R. and Wolf, B. A. and Kita, R.},
month = feb,
year = {2006},
keywords = {polymer-solutions, mixtures, poly(ethylene oxide), mass diffusion, molecular-dynamics, sign change, soret coefficient, structure breaker, thermodiffusion, theta-temperature},
pages = {435--440},
}
@article{bercea_enthalpy_2006,
title = {Enthalpy and entropy contributions to solvent quality and inversions of heat effects with polymer concentration},
volume = {207},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000240955500005&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.200600244},
abstract = {Vapor pressures above the solutions of polystyrene in either cyclohexane (32-60 degrees C) or toluene (10-70 degrees C) have been measured by a combination of head space sampling and gas chromatography as a function of the volume fraction phi of the polymer. The thus obtained Flory-Huggins interaction parameters chi (phi, T) were complemented by data for three other systems (tert-butyl acetate/polystyrene, cyclohexane/poly(vinyl methyl ether), 2-propanol/poly(butyl methacrylate)) reported in the literature and analyzed in terms of their enthalpy and entropy parts chi(H) and chi(S). Furthermore these experimental findings were modeled by means of an approach splitting the mixing process conceptually into two parts and lading to the expression chi = chi(fc) + chi(cr). The first step takes place at fixed conformation of the components and yields chi(fc); equilibrium is reached in the second step, during the conformational relaxation, contributing chi(cr). The results demonstrate that mixing can either be driven enthalpically or entropically. By contrast the conformational response acts in all cases towards homogeneous mixing. The inversion of heat effects observed for two of the five systems can be well modeled in terms of the composition dependence of the enthalpy parts of chi(fc) and chi(cr).},
language = {English},
number = {18},
journal = {Macromolecular Chemistry and Physics},
author = {Bercea, M. and Wolf, B. A.},
month = sep,
year = {2006},
keywords = {cooccurrence, temperature, thermoreversible gelation, flory-huggins interaction parameter, gas-chromatography, composition dependence, temperature dependence, clues, conformational variability, huggins interaction parameters, adequate thermodynamic description, chain connectivity, modeling, conformational response, dilute-solutions, inversion of heats of dilution},
pages = {1661--1673},
}
@article{calciu_inverse_2006,
title = {Inverse spin fractionation: a tool to fractionate sodium hyaluronate},
volume = {7},
issn = {1525-7797},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000242701600035&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Bm0605154},
language = {English},
number = {12},
journal = {Biomacromolecules},
author = {Calciu, D. and Eckelt, J. and Haase, T. and Wolf, B. A.},
month = dec,
year = {2006},
keywords = {degradation, large-scale fractionation, acid},
pages = {3544--3547},
}
@article{wolf_polyelectrolytes_2007,
title = {Polyelectrolytes revisited: {Reliable} determination of intrinsic viscosities},
volume = {28},
issn = {1022-1336},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000244080900004&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/marc.200600650},
abstract = {The linear extrapolation of (eta-eta(0))/(eta(0)c) towards c -{\textgreater} 0 constitutes the basis of traditional methods to determine intrinsic viscosities [eta], where eta is the viscosity of polymer solutions of concentration c and eta(0) is the viscosity of the pure solvent. With uncharged macromolecules this procedure works well; for polyelectrolytes it fails because of the pronounced non-linearity of the above dependence at high dilution resulting from the increasing electrostatic interactions. This contribution presents a new method for the determination of [eta]. It rests upon the application of the laws of phenomenological thermodynamics to the viscosity of polymer solutions and introduces a generalized intrinsic viscosity enabling a comparison of differently charged and uncharged polymers.},
language = {English},
number = {2},
journal = {Macromolecular Rapid Communications},
author = {Wolf, B. A.},
month = jan,
year = {2007},
keywords = {viscosity, polyelectrolytes, intrinsic viscosity, specific hydrodynamic volume},
pages = {164--170},
}
@article{calciu-rusu_rheology_2007,
title = {Rheology of sodium hyaluronate saline solutions for ophthalmic use},
volume = {8},
issn = {1525-7797},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000245510100031&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Bm061039k},
abstract = {The aim of this work was to investigate the rheological properties of different saline solutions of sodium hyaluronate (NaHA) with special interest for medical applications. The experimental results were compared with literature data for commercial ophthalmic viscosurgical devices (OVDs) used in cataract surgery. We offer some tools to tailor the rheological behavior of OVDs for different purposes. We have investigated to which extent surgical requirements can be fulfilled by adjusting either the molecular weight of NaHA or its concentration, parameters that are in some respects equivalent but not in others. Furthermore, we demonstrate that moduli and complex viscosities of NaHA saline solutions are adequately falling on master curves, using either empirical or calculated shift factors, the latest ones being based on a modified Rouse model.},
language = {English},
number = {4},
journal = {Biomacromolecules},
author = {Calciu-Rusu, D. and Rothfuss, E. and Eckelt, J. and Haase, T. and Dick, H. B. and Wolf, B. A.},
month = apr,
year = {2007},
keywords = {behavior, molecular-weight, derivatives, degradation, acid, viscosurgical devices},
pages = {1287--1292},
}
@article{eckelt_cellulosewater_2007,
title = {Cellulose/{Water}: {Liquid}/{Gas} and {Liquid}/{Liquid} phase equilibria and their consistent modeling},
volume = {8},
issn = {1525-7797},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000247107900015&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Bm070174+},
abstract = {Liquid/liquid and liquid/gas equilibria were measured for the water/cellulose system at 80 degrees C using three different polymer samples. For these experiments we prepared cellulose films of approximately 20-25 mu m in thickness and determined their equilibrium swelling in water. Thereafter the polymer concentration in the mixed phase was increased by means of a stepwise removal of the volatile component, and the equilibrium vapor pressures were measured using an automated combination of head space sampling and gas chromatography. Contrary to the usual behavior of polymers, the swelling of cellulose increases as its molar mass becomes larger. The Flory-Huggins interaction parameters calculated from the measured vapor pressures pass a pronounced minimum as a function of composition; for high cellulose contents they are negative, whereas they become positive for water-rich mixtures. All experimental findings are consistently interpreted by means of an approach accounting explicitly for the effects of chain connectivity and for the ability of macromolecules to respond to environmental changes by conformational rearrangement.},
language = {English},
number = {6},
journal = {Biomacromolecules},
author = {Eckelt, J. and Wolf, B. A.},
month = jun,
year = {2007},
keywords = {behavior, polymers, diagrams, water, gibbs energy, clues, conformational variability, adequate thermodynamic description, chain connectivity, methylmorpholine-n-oxide},
pages = {1865--1872},
}
@article{schnell_evolution_2008,
title = {Evolution of viscosities and morphology for the two-phase system polyethylene oxide/poly(dimethylsiloxane)},
volume = {47},
issn = {0035-4511},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000255414300010&action=retrieve&mode=FullRecord},
doi = {DOI 10.1007/s00397-007-0240-5},
abstract = {Shear viscosities and oscillatory viscosities were measured for the two-phase system polyethylene oxide/poly(dimethylsiloxane) at 70 degrees C as a function of composition. This blend exhibits the usual droplet/matrix structures in the vicinity of the pure components and a region of co-continuity within which two droplet/matrix structures coexist. A stepwise reduction in the shear rate,gamma, leads to a rapid increase in viscosity followed by a much slower exponential decay; plots of the corresponding rate constants as a function of composition exhibit two discontinuities marking the boundaries of co-continuity; a similar dependence is obtained for the time independent final viscosities eta(infinity). Keeping the blend composition constant and determining eta(infinity) as a function of gamma yields a curve that passes a distinct maximum, where the viscosities are very close to that of the less viscous pure component on both ends of this dependence. The dynamic mechanical measurements of the blends yield at low frequencies storage moduli G' that are orders of magnitude larger than that of the components because of the deformation of the interfaces. At high frequencies, the loss moduli G '' reflect the increasing alignment of the drops suspended in the matrix phases. The composition dependencies of G' and of the complex viscosities can again be used to determine the limits of co-continuity.},
language = {English},
number = {4},
journal = {Rheologica Acta},
author = {Schnell, M. and Ziegler, V. and Wolf, B. A.},
month = may,
year = {2008},
keywords = {flow, polymer blends, shear, immiscible polymer blends, state, loss modulus, storage modulus, coalescence, continuity, co-continuity, cocontinuity, phase morphology, rheological response, shear viscosity, two-phase morphology},
pages = {469--476},
}
@article{samadi_branched_2007,
title = {Branched versus linear polyisoprene: {Fractionation} and phase behavior},
volume = {43},
issn = {0014-3057},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000250386600018&action=retrieve&mode=FullRecord},
doi = {DOI 10.1016/j.eurpolymj.2007.08.002},
abstract = {Branched polyisoprene (PI) was prepared from PI-macromonomers. Linear byproducts of the synthesized polymer were removed by means of inverse spin fractionation, using the solvent cyclohexane (CH) and the precipitant acetone (AC). A Nvell-defined fraction (M-w = 17.5 kg/mol, M-w/M-n = 1.8) of the branched polyisoprene obtained in this manner was used to determine different phase diagrams with branched and/or linear PI in the mixed solvent CH/AC at 25 degrees C. For comparable molar masses of the polymers the two-phase area is smallest for the branched PI and slightly larger for the linear PI; in the case of the unfractionated original sample of the branched polymer one observes a pronounced peninsula of immiscibility extending into the region of high CH concentrations. This feature is attributed to a large miscibility gap between the branched and the linear polymer, which was studied in more detail for the ternary system CH/branched Pl/linear PI. (C) 2007 Elsevier Ltd. All rights reserved.},
language = {English},
number = {10},
journal = {European Polymer Journal},
author = {Samadi, F. and Eckelt, J. and Wolf, B. A. and Lopez-Villanueva, F. J. and Frey, H.},
month = oct,
year = {2007},
keywords = {angle neutron-scattering, blends, interaction parameters, architecture, separation, polymer fractionation, large-scale fractionation, compatibility of linear and branched polyisoprene, hyperbranched polymers, polyethylenes, polymer architecture, star, ternary phase diagram},
pages = {4236--4243},
}
@book{eckelt_continuous_nodate,
address = {2007},
series = {{POLYMERIC} {MATERIALS} {IN} {POWER} {ENGINEERING}},
title = {Continuous {Spin} {Fractionation}: {A} large scale method to improve the performance of polymers},
author = {Eckelt, John and Wolf, Bernhard Anton},
}
@article{eckelt_polyelectrolytes_2008,
title = {Polyelectrolytes: {Intrinsic} viscosities in the absence and in the presence of salt},
volume = {41},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000252944900058&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma702054f},
abstract = {Intrinsic viscosities were determined at 25 degrees C for 10 samples of narrowly distributed sodium polystyrene sulfonate (the molecular weights M ranging from 0.9 to 1000 kg/mol) in pure water and in aqueous solutions containing 0.9 wt \% NaCl from the slope of In eta(rel) versus polymer concentration. In the middle range of M, the [eta] values are in the former case almost 2 orders of magnitude larger than in the latter case. In the absence of salt, the plot of log [q] as a function of log M exhibits a sigmoidal shape, which can be approximated within the interval 3 {\textless} M (in kg mol(-1)) {\textless} 30 by log[eta] = -0.17 + 2.1 log M. In the presence of salt, the following relation holds true in the entire regime: log[eta] = -0. 13 + 0.86 log M. The concentration dependences of 'q of the present polyelectrolyte solutions and of solutions of uncharged polymers in organic solvents taken from the literature can be modeled quantitatively by means of recently reported relations at least up to reduced polymer concentration c[eta] = 5. The physical meaning of the parameters obtained from this modeling is surveyed.},
language = {English},
number = {3},
journal = {Macromolecules},
author = {Eckelt, J. and Knopf, A. and Wolf, B. A.},
month = feb,
year = {2008},
keywords = {pressure-dependence, clues, conformational variability, adequate thermodynamic description, chain connectivity, dilute, poly-electrolyte solutions},
pages = {912--918},
}
@article{bercea_random_2008,
title = {Random copolymers: {Their} solution thermodynamics as compared with that of the corresponding {Homopolymers}},
volume = {47},
issn = {0888-5885},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000254471800039&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ie0716619},
abstract = {Vapor pressure data (at 50 degrees C) of solutions of poly(methyl methacrylate) [PMMA], polystyrene [PS], and poly(styrene-ran-methyl methacrylate) [P(S-ran-MMA)], with different weight fractions f of styrene units, in either CHCl3, acetone [AC], methyl acetate [MeAc], or toluene [TL] were evaluated with respect to the dependence of the Flory-Huggins interaction parameter X on polymer concentration and on f. For all solutions under investigation, X varies considerably with the composition of the mixture, and only for four of them [CHCl3/PS, AC/PMMA, MeAc/PS, and TL/P(S-ran-MMA) f = 0.5] is this dependence linear; another four systems exhibit a minimum [CHCl3/PMMA, CHCl3/P(S-ran-MMA) f = 0.5, TL/PMMA, and TUPS], and only one [MeAc/PMMA] shows a maximum. With the exception of CHCl3/P(S-ran-MMA) and f = 0.5, the chi values of the copolymers do not fall reasonably between the data obtained for the corresponding homopolymers. In most cases, the incorporation of a small fraction of the monomer that interacts less favorably with a given solvent suffices to make the copolymer behave very similar to the worse soluble homopolymer. In order to rationalize these multifaceted findings, we have modeled the results by means of an expression for chi, which accounts explicitly for the chain connectivity of polymers and for the capability of the components to change their molecular conformation upon mixing. This approach yields a consistent picture of the present results; it reproduces the effects of polymer concentration On v quantitatively by means of three physically meaningful parameters. The modeling of the influences of copolymer composition requires one additional term for each of these parameters.},
language = {English},
number = {7},
journal = {Industrial \& Engineering Chemistry Research},
author = {Bercea, M. and Eckelt, J. and Wolf, B. A.},
month = apr,
year = {2008},
keywords = {polymer-solutions, behavior, mixtures, clues, conformational variability, huggins interaction parameters, chain connectivity, organic-solvents, phase-equilibria, sorption phenomena},
pages = {2434--2441},
}
@article{eckelt_thermodynamic_2008,
title = {Thermodynamic interaction parameters for the system water/{NMMO} hydrate},
volume = {112},
issn = {1520-6106},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000253945900019&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Jp710869e},
abstract = {Vapor pressures of water were measured for aqueous solutions of N-methyl-morpholine N-oxide (NMMO) at 80, 90 and 100 degrees C. The Flory-Huggins interaction parameters, chi, calculated from these data as a function of phi, the volume fraction of NMMO, are negative at all concentrations; at low phi, they decrease by more than a factor of 2 as T is raised, whereas they remain almost unchanged as phi approaches unity. Accordingly, the heat of mixing is pronouncedly endothermal at low NMMO concentrations but close to athermal at low water content. The composition dependence of chi can be equally well described by the Redlich-Kister equation and by an approach subdividing the mixing process into two separate steps. The opportunities of the latter modeling for a better molecular understanding of the mixing processes are discussed.},
language = {English},
number = {11},
journal = {Journal of Physical Chemistry B},
author = {Eckelt, J. and Wolf, B. A.},
month = mar,
year = {2008},
keywords = {diagrams, derivatives, cellulose, gibbs energy, phase-behavior, chain connectivity, methylmorpholine-n-oxide},
pages = {3397--3401},
}
@article{butt_forces_2007,
title = {Forces between solid surfaces across polymer melts as revealed by atomic force microscopy},
volume = {5},
issn = {1539-445X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000251333800002&action=retrieve&mode=FullRecord},
doi = {Doi 10.1080/15394450701554411},
abstract = {Forces between solid surfaces across polymer melts are poorly understood despite their fundamental importance and their relevance for making composite materials. Such force measurements reveal information on the structure of polymers at surfaces and of confined polymers. Experiments with the atomic force microscope and polyisoprene ( PI) confirmed theoretical predictions that no long-range force should be present in thermodynamic equilibrium. In poly( dimethyl siloxane) ( PDMS) repulsive forces are observed at high molar mass. We attribute this to the formation of an immobilized layer caused by a slow release of adsorbed segments enhanced by entanglement. In low molar mass PDMS attractive forces were observed which we can not yet explain. Attaching a hydroxyl end group to PI or PDMS chains lead to repulsive forces caused by the formation of a brush-like structure.},
language = {English},
number = {2-3},
journal = {Soft Materials},
author = {Butt, H. J. and Wang, J. J. and Stark, R. and Kappl, M. and Wolf, B. A. and Eckelt, J. and Knopf, A.},
year = {2007},
keywords = {shear, adhesion, copolymers, model, equilibrium, adsorbing surfaces, chains, composites, confined polymer, good solvent, nanorheology, plates, sfm, surface force, thin-film},
pages = {49--60},
}
@article{eckelt_pullulan_2008,
title = {Pullulan and dextran: {Uncommon} composition dependent {Flory}-{Huggins} interaction parameters of their aqueous solutions},
volume = {9},
issn = {1525-7797},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000256635100025&action=retrieve&mode=FullRecord},
doi = {10.1021/bm800217y},
abstract = {Vapor pressure measurements were performed for aqueous solutions of pullulan (M-w 280 kg/mol) and dextran (Mw 60 and 2100 kg/mol, respectively) at 25, 37.5, and 50 degrees C. The Flory-Huggins interaction parameters obtained from these measurements, plus information on dilute solutions taken from the literature, show that water is a better solvent for pullulan than for dextran. Furthermore, they evince uncommon composition dependencies, including the concurrent appearance of two extrema, a minimum at moderate polymer concentration and a maximum at high polymer concentration. To model these findings, a previously established approach, subdividing the mixing process into two clearly separable steps, was generalized to account for specific interactions between water and polysaccharide segments. Three adjustable parameters suffice to describe the results quantitatively; according to their numerical values, the reasons for the solubility of polysaccharides in water, as compared with that of synthetic polymers in organic solvents, differ in a principal manner. In the former case, the main driving force comes from the first step (contact formation between the components), whereas it is the second step (conformational relaxation) that is advantageous in the latter case.},
language = {English},
number = {6},
journal = {Biomacromolecules},
author = {Eckelt, J. and Sugaya, R. and Wolf, B. A.},
month = jun,
year = {2008},
keywords = {system, behavior, temperature, scattering, water, thermodynamic interaction parameters},
pages = {1691--1697},
}
@article{badiger_intrinsic_2008,
title = {Intrinsic {Viscosity} of {Aqueous} {Solutions} of {Carboxymethyl} {Guar} in the {Presence} and in the {Absence} of {Salt}},
volume = {209},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000260640600003&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.200800238},
abstract = {Intrinsic viscosities were determined for solutions of CMG in pure water and 0.9 wt.-\% aqueous NaCl. To avoid the 0/0-type extrapolation typical for Huggins plots, a new procedure was used. For CMG and pure water, this requires only two adjustable parameters: the specific hydrodynamic volume of the polymer in the limit of infinite dilution and a hydrodynamic interaction parameter. The intrinsic viscosity of CMG (no salt) at room temperature is 6 050 mL . g(-1); approximately half as large as that of Na-PSS of comparable molar mass. The ratio of the intrinsic viscosities with and without salt is approximate to 7 for CMG, as compared to {\textgreater}100 for Na-PSS. The reasons 1:5 5 for the different behaviors of the two types of polyelectrolytes are being discussed.},
language = {English},
number = {20},
journal = {Macromolecular Chemistry and Physics},
author = {Badiger, M. V. and Gupta, N. R. and Eckelt, J. and Wolf, B. A.},
month = oct,
year = {2008},
keywords = {polyelectrolytes, intrinsic viscosity, biopolymers, carboxymethyl guar, controlled grafting processes, gum, polyelectrolyte, salt-free solutions},
pages = {2087--2093},
}
@article{samadi_branched_2008,
title = {Branched versus {Linear} {Polyelectrolytes}: {Intrinsic} {Viscosities} of {Peripherically} {Charged} {Dendronized} {Poly}(methyl methacrylate)s and of {Their} {Uncharged} {Analogues}},
volume = {41},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000260612700057&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma801088h},
abstract = {Viscosities of dilute solutions were measured for four generations of peripherically charged dendronized poly(methyl methacrylate)s (CDPs) of two different chain lengths in water (no salt added) and of their uncharged analogues (UCPs) in chloroform. In all cases it was possible to describe In(eta(solution)/eta(solvent)) as a function of polymer concentration by two adjustable parameters: a hydrodynamic interaction parameter B and [eta], the intrinsic viscosity of the polymer. The [eta] values for the first generation of polyelectrolytes are markedly lower (given number of monomeric units) than that of aqueous solutions of Na-polystyrene sulfonate reported earlier, despite the fact that each monomeric unit is much larger and bears two charges instead of one; as the number of generation rises, [eta] falls markedly for the CDPs as well as for the UCPs, where the effect is considerably more pronounced for the polyelectrolyte. The increase in molar mass M associated with the addition of dendrons leads to a maximum in the molar hydrodynamic volume [eta]M for the second generation of the CDP; in case of the UCPs this volume increases steadily. The interaction parameter B is normally positive but may for the higher generations become negative, corresponding to a more than exponential augmentation of eta with polymer concentration. A consistent description of the findings is presented in terms of intra- and intermolecular interactions between the -NH and -O- groups of the dendrons and the distances of the charges from the polymer backbone.},
language = {English},
number = {21},
journal = {Macromolecules},
author = {Samadi, F. and Wolf, B. A. and Guo, Y. F. and Zhang, A. and Schluter, A. D.},
month = nov,
year = {2008},
keywords = {dependence, polymer-solutions, dilute-solutions, complexes, molecules},
pages = {8173--8180},
}
@article{wolf_binary_2009,
title = {Binary {Interaction} {Parameters}, {Ternary} {Systems}: {Realistic} {Modeling} of {Liquid}/{Liquid} {Phase} {Separation}},
volume = {18},
issn = {1022-1344},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000262963900004&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/mats.200800065},
abstract = {The phase behavior of ternary systems (either a polymer solution in a mixed solvent or a polymer blend in a single solvent) was modeled theoretically. The modeling considers two specific features of polymers explicitly: chain connectivity and the ability to respond to changes in the molecular environment by conformational reorientation. Previously, this approach has been applied to polymer solutions in single solvents. Here it is generalized and the number of parameters is reduced to two per binary system. The calculation of the Gibbs energies of the ternary mixtures accounts for the composition dependencies of the binary interaction parameters. The following phenomena are reproduced realistically for polymer solutions in a mixed solvent and for solutions of two polymers in a common solvent: simplicity, co-solvency, and co-non-solvency. The results nourish the hope that the new approach is capable of modeling phase diagrams for ternary systems by means of binary interaction parameters only.},
language = {English},
number = {1},
journal = {Macromolecular Theory and Simulations},
author = {Wolf, B. A.},
month = jan,
year = {2009},
keywords = {polystyrene, polyvinyl methyl-ether), polymer-solutions, angle neutron-scattering, thermodynamics, derivatives, gibbs energy, conformational variability, adequate thermodynamic description, chain connectivity, co-non-solvency, co-solvency, liquid/liquid demixing, mixed-solvents, phase diagrams of ternary systems},
pages = {30--41},
}
@article{eckelt_phase_2009,
title = {Phase diagram of the ternary system {NMMO}/water/cellulose},
volume = {16},
issn = {0969-0239},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000265831500003&action=retrieve&mode=FullRecord},
doi = {DOI 10.1007/s10570-009-9276-2},
abstract = {The phase diagram of the system N-methylmorpholine-N-oxide(NMMO)/H(2)O/cellulose has been measured at 80 A degrees C by establishing a solubility map (observation of the mixtures under the microscope), by the analysis of coexisting phases and determining the critical point. These experiments manifest a continuous reduction of the two phase area existing for the subsystem H(2)O/cellulose upon the addition of NMMO, where a weight fraction of NMMO in the mixed solvent exceeding 75 wt\% is required for Solucell 400 to reach the critical composition. The critical cellulose concentration is only 0.34 wt\%, i.e., more than an order of magnitude lower than for the solutions of typical vinyl polymers in mixed solvents. All experimental observations can be well modeled on the basis of composition dependent binary interaction parameters by means of recently established mixing rules. For the subsystems H(2)O/cellulose and NMMO/water the corresponding data are known from independent earlier measurements. The adjustment of two parameters to the ternary phase diagram was required to obtain this information for NMMO/cellulose, the third binary subsystem.},
language = {English},
number = {3},
journal = {Cellulose},
author = {Eckelt, J. and Eich, T. and Roder, T. and Ruf, H. and Sixta, H. and Wolf, B. A.},
month = jun,
year = {2009},
keywords = {dependence, polystyrene, interaction parameter, mixtures, separation, cellulose, phase diagram, unsubstituted cellulose, huggins interaction parameters, lyocell, nmmo, volumes},
pages = {373--379},
}
@article{ghimici_ionic_2009,
title = {Ionic {Polymers} {Based} on {Dextran}: {Hydrodynamic} {Properties} in {Aqueous} {Solution} and {Solvent} {Mixtures}},
volume = {113},
issn = {1520-6106},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000266679200010&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Jp900690f},
abstract = {Hydrodynamic properties of a series of ionic polysaccharides with different charge density but the same molecular weight have been evaluated in salt-free aqueous solution and aqueous/organic solvent mixtures by means of capillary viscometry. The polyelectrolytes investigated contain quaternary ammonium salt groups, N-ethyl-N,N-dimethyl-2-hydroxypropylammonium chloride, attached to a dextran backbone. The experimental viscometric data have been plotted in terms of the Wolf method. The results show that the experimental data fit well with this model and allow the calculation of intrinsic viscosities and other hydrodynamic parameters, which provide new information about the dependence of the polyion conformation on its polyion charge density as well as on solvent composition.},
language = {English},
number = {23},
journal = {Journal of Physical Chemistry B},
author = {Ghimici, L. and Nichifor, M. and Wolf, B.},
month = jun,
year = {2009},
keywords = {cationic polyelectrolytes, counterion-condensation, electrolyte solutions, intrinsic-viscosity, molecular-weight relationship, polar-solvent, polyelectrolyte solutions, reduced viscosity, salt-free solution, viscometric behavior},
pages = {8020--8025},
}
@article{bercea_vapor_2009,
title = {Vapor {Pressures} of {Polymer} {Solutions} and the {Modeling} of {Their} {Composition} {Dependence}},
volume = {48},
issn = {0888-5885},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000265781200047&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ie801965h},
abstract = {Equilibrium vapor pressures, p, are reported for the systems tetrahydrofuran + poly(vinyl methyl ether) and tetrahydrofuran + polystyrene at 20, 40, and 60 degrees C. These data plus information from the literature serve to demonstrate that the composition dependence of p can be modeled quantitatively for polymer Solutions in thermodynamically very different solvents by means of three, physically meaningful parameters.},
language = {English},
number = {9},
journal = {Industrial \& Engineering Chemistry Research},
author = {Bercea, M. and Eckelt, J. and Wolf, B. A.},
month = may,
year = {2009},
keywords = {polystyrene, huggins interaction parameters},
pages = {4603--4606},
}
@article{bercea_islands_2009,
title = {Islands of {Immiscibility} for {Solutions} of {Compatible} {Polymers} in a {Common} {Solvent}: {Experiment} and {Theory}},
volume = {42},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000266200800025&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma9002769},
abstract = {Experimentally obtained islands of immiscibility are reported for the systems PS/PVME/THF at 20 degrees C and for PS/PVME/CH at 55 degrees C (PS: polystyrene, PVME: poly(vinyl methyl ether), THE tetrahydrofuran, CH: cyclohexane). THF is a good solvent and CH is a marginal solvent for both polymers. In the case of THF, information on the Flory-Huggins interaction parameters of the three binary subsystems suffices for a qualitative prediction of the phase behavior of the ternary system. Quantitative agreement can be achieved by means of composition-independent ternary interaction parameters. For the marginal solvent CH, the exclusive use of binary interaction parameters wrongly predicts complete miscibility of all three components. In this case, one ternary interaction parameter must be treated as a function of composition in order to match experiment and theory. On the basis of the present results, it can be concluded that the preparation of homogeneous mixtures with arbitrary composition from a pair of compatible polymers and a common solvent is only possible on rare occasions.},
language = {English},
number = {10},
journal = {Macromolecules},
author = {Bercea, M. and Eckelt, J. and Morariu, S. and Wolf, B. A.},
month = may,
year = {2009},
keywords = {polystyrene, interaction parameters, phase-diagrams, derivatives, separation, gibbs energy, chain connectivity, ether)},
pages = {3620--3626},
}
@article{morariu_fractionation_2009,
title = {Fractionation of {Poly}(vinyl methyl ether): {Comparison} of {Two} {Large}-{Scale} {Fractionation} {Techniques}},
volume = {48},
issn = {0888-5885},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000268479500006&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ie900484g},
abstract = {The efficiencies of two large-scale fractionation techniques namely continuous polymer fractionation (CPF) and continuous spin fractionation (CSF) are compared. To this end, we used a commercially available sample of poly(vinyl methyl ether). Both methods ire suitable to reduce the nonuniformity of the sample below 0.6. The results demonstrate that CSF has a better fractionation performance than the progenitor method, CPF. A further advantage is the three times higher throughput of CSF.},
language = {English},
number = {15},
journal = {Industrial \& Engineering Chemistry Research},
author = {Morariu, S. and Eckelt, J. and Wolf, B. A.},
month = aug,
year = {2009},
keywords = {continuous polymer fractionation, ether), transfer radical polymerization},
pages = {6943--6948},
}
@article{eckelt_branched_2009,
title = {Branched {Versus} {Linear} {Polyisoprene}: {Flory}-{Huggins} {Interaction} {Parameters} for their {Solutions} in {Cyclohexane}},
volume = {210},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000270148400009&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.200900191},
abstract = {Flory-Huggins interaction parameters were determined as a function of composition for solutions of linear and of branched polyisoprene in cyclohexane (CH) at 25, 45, and 65 degrees C by means of vapor pressure measurements (moderate to concentrated solutions) and by vapor pressure osmometry (dilute solutions). The results demonstrate that CH is a considerably worse solvent for branched polyisoprene than for the linear analog at all temperatures and at all compositions. This observation corroborates the expectation based on a recent phenomenological approach, which accounts explicitly for the incapability of the segments of an individual polymer molecule to spread out over the entire volume of the system and for its ability to adjust its chain conformation to an altering molecular environment.},
language = {English},
number = {17},
journal = {Macromolecular Chemistry and Physics},
author = {Eckelt, J. and Samadi, F. and Wurm, F. and Frey, H. and Wolf, B. A.},
month = sep,
year = {2009},
keywords = {cyclohexane, behavior, blends, concentration-dependence, solvent quality, flory-huggins interaction parameters, theta-temperature, branched, intramolecular interaction parameters, linear, liquid phase-separation, molecular architecture, ordering phenomena, semidilute solutions, star polymers, vapor pressure},
pages = {1433--1439},
}
@article{wolf_polymer_2010,
title = {Polymer {Incompatibility} {Caused} by {Different} {Molecular} {Architectures}: {Modeling} via {Chain} {Connectivity} and {Conformational} {Relaxation}},
volume = {19},
issn = {1022-1344},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000274809800004&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/mats.200900049},
abstract = {The calculation of phase diagrams for blends of linear and branched polymers made up of identical monomeric units is modeled using an approach that subdivides the mixing process into two steps: i) contact formation between the different components, keeping their chain conformations and the volume of the system constant; and, ii) relaxation of the macromolecules into their equilibrium state by molecular rearrangements. It is assumed that step (ii) causes shape-induced polymer incompatibility and that the degree of branching can be quantified in terms of the volumes the isolated coils of the branched polymer occupy in relation to the volume the linear product with the same molecular weight occupies. Under these premises, it is possible to work out how the critical conditions depend on the molar masses of the components and on the degree of branching of the non-linear polymer by means of only one system-specific parameter, measuring the effects of conformational relaxation. Detailed phase diagrams show how the binodal and spinodal conditions reflect the conformational variability of the blend components.},
language = {English},
number = {1},
journal = {Macromolecular Theory and Simulations},
author = {Wolf, B. A.},
month = feb,
year = {2010},
keywords = {behavior, angle neutron-scattering, thermodynamics, blends, copolymers, phase diagram, adequate thermodynamic description, modeling, variability, liquid phase-separation, branched polyethylenes, branched polymers, effective interaction parameter, incompatibility, segregation},
pages = {36--43},
}
@article{xiong_thermodynamics_2009,
title = {Thermodynamics of {Block} {Copolymer} {Solutions} {As} {Compared} with the {Corresponding} {Homopolymer} {Solutions}: {Experiment} and {Theory}},
volume = {42},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000271233600053&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma9014615},
abstract = {The interaction of butadiene-styrene block copolyincis of different molecular architecture with tetrahydrofuran (THF) was studied by vapor pressure and light scattering experiments in the temperature range from 25 to 55 degrees C The thus obtained Flory-Huggins interaction parameters, chi, as a function of phi, the volume fraction of the polymers, were compared with that of the corresponding homopolymersim in the same solvent The results are very similar for all block copolymers (diblock, triblock and star-shaped, butadlene In the chi(phi) Curves of the homopolymers, which are always located center) and for all temperatures In contrast to they chi(phi) curves of the homopolymers, which are always located above their tangents, the dependencies for the block copolymers exhibit it maximum in the range of moderate polymer concentrations, where the heats of dilution are close to athermal ill the range of low phi values but become pronouncedly endoiliernial rot high phi values These Findings call be well modeled by all approach considering the phenomena of chain connectivity and conformational relaxation of polymers , If one accounts for the unfavorable interactions between the monomeric units of the different blocks},
language = {English},
number = {21},
journal = {Macromolecules},
author = {Xiong, X. P. and Eckelt, J. and Zhang, L. and Wolf, B. A.},
month = nov,
year = {2009},
keywords = {polymer-solutions, chromatography, model, phase-behavior, composition dependence, clues, conformational variability, huggins interaction parameters, chain connectivity, binary-mixtures},
pages = {8398--8405},
}
@article{samadi_branched_2010,
title = {Branched {Versus} {Linear} {Oligo}(dimethylsiloxane): {Differences} in {Their} {Thermodynamic} {Interaction} with {Solvents}},
volume = {48},
issn = {0887-6266},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000278750600008&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/Polb.22029},
abstract = {The thermodynamic behavior of linear and of branched oligo(dimethylsiloxane) (O-DMS) solutions was studied by means of vapor pressure measurements and vapor pressure osmometry at different temperatures for the thermodynamically favorable solvent THF. The branched material required for that purpose was synthesized and afterwards fractionated by means of the single solvent acetone to eliminate components of low degrees of branching. The Flory-Huggins interaction parameters, chi, for the systems THF/O-DMS as a function of composition pass a minimum at all temperatures (25, 40, and 60 degrees C) in the case of the branched material. For the unbranched oligomer such a minimum is only observed at 60 degrees C. At 40 degrees C the results are ambigous whereas the dependence is definitely linear at 25 degrees C. This exceptional behavior of the linear product at the latter temperature is tentatively attributed to the formation of favorable orientational order in the pure state under these conditions. At high oligomer concentrations THF interacts more favorably with the branched material, however, this preference is reversed upon dilution. All measured composition dependencies of chi can be modeled quantitatively by an approach accounting for chain connectivity and for the ability of the oligomers to change their conformation upon dilution. (C) 2010 Wiley Periodicals, Inc. J Polym Sc) Part B: Polym Phys 48: 1309-1318, 2010},
language = {English},
number = {12},
journal = {Journal of Polymer Science Part B-Polymer Physics},
author = {Samadi, F. and Eckelt, J. and Wolf, B. A. and Schule, H. and Frey, H.},
month = jun,
year = {2010},
keywords = {systems, thermodynamics, fractionation, flory-huggins interaction parameter, composition dependence, huggins interaction parameters, polysiloxanes, branched, linear, molecular architecture, vapor pressure, alkanes, linear and branched oligomers, oligomers, solution properties, solution thermodynamics},
pages = {1309--1318},
}
@article{eckelt_viscosity-molecular_2011,
title = {Viscosity-{Molecular} {Weight} {Relationship} for {Cellulose} {Solutions} in {Either} {NMMO} {Monohydrate} or {Cuen}},
volume = {119},
issn = {0021-8995},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000284206900006&action=retrieve&mode=FullRecord},
doi = {Doi 10.1002/App.32785},
abstract = {The intrinsic viscosities, [eta], of nine cellulose samples, with molar masses from 50 x 10(3) to 1 390 x 10(3) were determined in the solvents NMMOH(2)O (N-methyl morpholin N-oxide hydrate) at 80 degrees C and in cuen (copper II-ethlenediamine) at 25 degrees C. The evaluation of these results with respect to the Kuhn-Mark-Houwink relations shows that the data for NMMOH(2)O fall on the usual straight line in the double logarithmic plots only for M {\textless}= 158 10(3); the corresponding [eta]/M relation reads log ([g]/mL g(-1)) = -1.465 + 0.735 log M. Beyond that molar mass [eta] remains almost constant up to M approximate to 10(6) and increases again thereafter. In contrast to NMMO*H(2)O the cellulose solutions in cuen behave normal and the Kuhn-Mark-Houwink relation reads log ([eta]/mL g(-1)) = -1.185 + 0.735 log M. Possible reasons for the dissimilarities of the behavior of cellulose in these two solvents are being discussed. The comparison of three different methods for the determination of [eta] from viscosity measurements at different polymer concentrations, c, demonstrates the advantages of plotting the natural logarithm of the relative viscosities as a function of c. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 670-676, 2011},
language = {English},
number = {2},
journal = {Journal of Applied Polymer Science},
author = {Eckelt, J. and Knopf, A. and Roder, T. and Weber, H. K. and Sixta, H. and Wolf, B. A.},
month = jan,
year = {2011},
keywords = {dependence, polymer-solutions, polyelectrolytes, cellulose, intrinsic viscosity, cuen, intrinsic viscosities, kuhn-mark-houwink relation, n-oxide-monohydrate, nmmo hydrate},
pages = {670--676},
}
@incollection{enders_notitle_2011,
address = {Heidelberg},
series = {Advances in {Polymer} {Science}},
volume = {238},
booktitle = {Recent developments in polymer thermodynamics},
publisher = {Springer Verlag},
author = {Enders, Sabine and Wolf, Bernhard Anton},
year = {2011},
}
@book{enders_polymer_2011,
address = {Berlin Heidelberg},
series = {Advances in {Polymer} {Science}},
title = {Polymer {Thermodynamics} {Liquid} {Polymer}-{Containg} {Mixtures}},
isbn = {978-3-642-17681-4},
number = {238},
publisher = {Springer Verlag},
author = {Enders, Sabine and Wolf, Bernhard Anton},
year = {2011},
}
@article{wolf_making_2011,
title = {Making {Flory}-{Huggins} {Practical}: {Thermodynamics} of {Polymer}-{Containing} {Mixtures}},
volume = {238},
issn = {0065-3195},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000296273400001&action=retrieve&mode=FullRecord},
doi = {Doi 10.1007/12_2010_84},
abstract = {The theoretical part of this article demonstrates how the original Flory-Huggins theory can be extended to describe the thermodynamic behavior of polymer-containing mixtures quantitatively. This progress is achieved by accounting for two features of macromolecules that the original approach ignores: the effects of chain connectivity in the case of dilute solutions, and the ability of polymer coils to change their spatial extension in response to alterations in their molecular environment. In the general case, this approach leads to composition-dependent interaction parameters, which can for most binary systems be described by means of two physically meaningful parameters; systems involving strongly interacting components, for instance via hydrogen bonds, may require up to four parameters. The general applicability of these equations is illustrated in a comprehensive section dedicated to the modeling of experimental findings. This part encompasses all types of phase equilibria, deals with binary systems (polymer solutions and polymer blends), and includes ternary mixtures; it covers linear and branched homopolymers as well as random and block copolymers. Particular emphasis is placed on the modeling of hitherto incomprehensible experimental observations reported in the literature.},
language = {English},
number = {238},
journal = {Advances in Polymer Science},
author = {Wolf, B. A.},
year = {2011},
keywords = {polymer solutions, polymer blends, thermodynamics, molecular-weight, interaction parameters, phase diagrams, gibbs energy, mixed solvents, phase-behavior, ternary mixtures, conformational variability, modeling, high molar masses, zero critical concentrations, equation-of-state, long-chain compounds, vapor-pressure osmometry},
pages = {1--66},
}
@article{eckelt_thermodynamic_2010,
title = {Thermodynamic interactions of natural and of man-made cellulose fibers with water},
volume = {17},
issn = {0969-0239},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000283298800003&action=retrieve&mode=FullRecord},
doi = {DOI 10.1007/s10570-010-9443-5},
abstract = {The vapor pressure of water was measured for binary mixtures with cellulose containing fabrics at 37 A degrees C by means of two complementary methods. Different types of fabrics were studied: One consisting exclusively of cellulose fibers, either of natural origin (cotton) or regenerated from solutions in the mixed solvent NMMO/water (Lyocell fibers, CLY) and another kind of fabric containing polyethylene terephthalate (PET) fibers in addition to CLY fibers. The Flory-Huggins interaction parameters chi and their composition dependence calculated from these vapor pressure data are broadly similar for cotton and for CLY, apart from the fact that water interacts somewhat more favorably with CLY than with cotton. In both cases the chi values pass successively a maximum and a minimum as the concentration of water rises. The experiments performed with the fabrics containing two types of fibers demonstrate that the water uptake of PET is negligible as compared with that of cellulose. The results for the system water/cellulose fibers obtained at 37 A degrees C differ fundamentally from corresponding data for 80 A degrees C, reported for cellulose films prepared from solutions in dimethylacetamide + LiCl. The maximum water uptake of cellulose is determined by its degree of crystallinity. In all cases it is possible to model the Flory-Huggins interaction parameters as a function of composition quantitatively by means of an approach subdividing the dilution process conceptually into two separate steps: Contact formation between the dissimilar components (keeping their conformation constant) and subsequent relaxation of the system into the equilibrium state. Similarities and dissimilarities of the systems water/polysaccharide are being discussed in detail.},
language = {English},
number = {6},
journal = {Cellulose},
author = {Eckelt, J. and Richardt, D. and Schuster, K. C. and Wolf, B. A.},
month = dec,
year = {2010},
keywords = {polymers, huggins interaction parameters, flory-huggins interaction parameters, cellulose fibers, mixed cellulose fibers, vapor pressure measurements, water retention},
pages = {1079--1093},
}
@incollection{eckelt_characterization_2012,
address = {Amsterdam},
series = {Comprehensive {Polymer} {Science}},
title = {Characterization by {Separation} {Methods} / {Fractionation}},
booktitle = {In: {Matyjaszewski} {K} and {Möller} {M} (eds.) {Polymer} {Science}: {A} {Comprehensive} {Reference}},
publisher = {Elsevier BV},
author = {Eckelt, John and Mascos, Michael and Wolf, Bernhard Anton},
year = {2012},
keywords = {[Author(s) (2012) [Chapter title]. In: Matyjaszewski K and Möller M (eds.) Polymer Science: A Comprehensive Reference, vol. [x], pp. [x]-[x]. Amsterdam: Elsevier BV.},
pages = {65--91},
}
@article{wolf_solubility_2011,
title = {Solubility of {Polymers}},
abstract = {The process of dissolving a pure polymer begins with solvent molecules permeating bulk polymer. Usually, this requires more energy and is slower if the polymer is crystalline than if it is liquid, rubbery or glassy. The polymer near the interface swells to accommodate the incoming molecules of solvent while individual long-chain molecules may be freed from near the interface and diffuse into the solvent phase. If the solubility limit is not exceeded, the system eventually becomes homogeneous. The extent to which the solution process can occur depends especially on the temperature, the chemical nature of solute and solvent, the molecu-lar weight of the polymer, and on the degree of crystallinity for semi crystalline polymers.},
journal = {Encyclopedia of Polymer Science and Technology},
author = {Wolf, B. A.},
month = jan,
year = {2011}
}
@article{ghimici_intrinsic_2012,
title = {Intrinsic viscosities of polyelectrolytes in the absence and in the presence of extra salt: {Consequences} of the stepwise conversion of dextran into a polycation},
volume = {87},
issn = {0144-8617},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000297389000054&action=retrieve&mode=FullRecord},
doi = {DOI 10.1016/j.carbpol.2011.07.067},
abstract = {Viscosities of dilute polymer solutions were measured in capillary viscometers for samples varying in their fraction f of charged units from 0.00 to 0.90. The dependence of the logarithm of the relative viscosity on polymer concentration c is in all cases reproduced quantitatively by three characteristic parameters: [eta], the intrinsic viscosity: B, a viscometric interaction parameter (related to the Huggins constant); [eta](center dot) a parameter required only for polyelectrolytes at low concentrations of extra salt. In pure water increases more than 80 times as the fraction f rises from zero to 0.90 and [eta](center dot) starts from zero and goes up to approximate to 71 mL/g. Upon the addition of NaCl [eta] decreases by at least one order of magnitude (depending on the value off). The observed dependences of log [eta] on log c(salt) can be modeled quantitatively by Boltzmann sigmoids. (C) 2011 Elsevier Ltd. All rights reserved.},
language = {English},
number = {1},
journal = {Carbohydrate Polymers},
author = {Ghimici, L. and Nichifor, M. and Eich, A. and Wolf, B. A.},
month = jan,
year = {2012},
keywords = {solvent, interaction parameter, copolymers, model, ionic-strength, dilute, cationic dextran derivative, coefficients, colligative properties, concentrated polymer-solutions, intrinsic viscosity hydrodynamic, polyelectrolyte solution, salt effect},
pages = {405--410},
}
@article{morariu_dextran-based_2011,
title = {Dextran-{Based} {Polycations}: {Thermodynamic} {Interaction} with {Water} as {Compared} {With} {Unsubstituted} {Dextran}, 1-{Volumetric} {Properties} and {Light} {Scattering}},
volume = {212},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000294229700011&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.201100196},
abstract = {Dextran and random dextran-based copolymers containing different molar fractions f of charged units are studied in aqueous solution and in the pure state. The specific volumes of the solutions decrease linearly with increasing weight fraction of the polymer. Extrapolation to the pure state yields information on the hypothetical liquid polymers, exhibiting a pronounced minimum at f approximate to 0.1. A similar dependence is also observed for the pure solid polymers; however, the specific volumes at low f are considerably larger and at high f are slightly smaller. These differences are discussed in terms of the non-equilibrium structures formed during sample preparation. The thermal expansivities of the solutions pass through a maximum at f approximate to 0.1. Light scattering shows that the thermodynamic quality of water has a minimum at f approximate to 0.1.},
language = {English},
number = {17},
journal = {Macromolecular Chemistry and Physics},
author = {Morariu, S. and Eckelt, J. and Wolf, B. A.},
month = sep,
year = {2011},
keywords = {density, polymers, polyelectrolytes, polysaccharides, solution properties, light scattering},
pages = {1925--1931},
}
@article{bercea_dextran-based_2011,
title = {Dextran-{Based} {Polycations}: {Thermodynamic} {Interaction} with {Water} as {Compared} {With} {Unsubstituted} {Dextran}, 2-{Flory}/{Huggins} {Interaction} {Parameter}},
volume = {212},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000294229700012&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.201100197},
abstract = {The Flory-Huggins interaction parameter chi is determined as a function of volume fraction of polymer phi by vapor-pressure measurements at 25, 37.5 and 50 degrees C for five dextran samples that differ in f, the fraction of randomly distributed charged monomer units. The function chi(phi) has a minimum that is shifted towards lower chi values as f increases. The higher the temperature, the more the individual curves fan out. The heats of dilution at high polymer concentrations change from exothermal to endothermal as f increases. The results can be well modeled by an approach accounting explicitly for chain connectivity and conformational changes. A smooth transition of the solution properties upon the random introduction of charged units into dextran is observed.},
language = {English},
number = {17},
journal = {Macromolecular Chemistry and Physics},
author = {Bercea, M. and Nichifor, M. and Eckelt, J. and Wolf, B. A.},
month = sep,
year = {2011},
keywords = {polymers, polyelectrolytes, clues, conformational variability, chain connectivity, modeling, aqueous-solutions, polysaccharides, solution properties, water-soluble polymers},
pages = {1932--1940},
}
@article{eich_intrinsic_2011,
title = {Intrinsic {Viscosities} of {Polyelectrolytes}: {Determination} and {Modeling} of the {Effects} of {Extra} {Salt}},
volume = {12},
issn = {1439-4235},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000297017600017&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/cphc.201100439},
abstract = {Based on early measurements of J. J. Hermans and co-workers (D. T. F. Pals, J. J. Hermans, Recl. Trav. Chim. Pays-Bas 1952, 71, 513-520; D. T. F. Pals, J. J. Hermans, J. Polym. Sci. 1950, 5, 733-734; D. T. F. Pals, J. J. Hermans, J. Polym. Sci. 1948, 3, 897-898), the present contribution demonstrates how primary data should be evaluated in order to obtain reliable intrinsic viscosities. This procedure yields detailed information on the changes of the intrinsic viscosities and of the corresponding viscometric interaction parameters caused by an increasing salinity of water. Both quantities decline from a maximum value in the pure solvent to a minimum value, which is approached in the limit of sufficiently high salt concentrations, and can be modeled quantitatively by means of a Boltzmann sigmoid. Particular attention is paid to the significance of results obtained by means of the method of isoionic dilution, proposed by J. J. Hermans and co-workers.},
language = {English},
number = {15},
journal = {Chemphyschem},
author = {Eich, A. and Wolf, B. A.},
month = oct,
year = {2011},
keywords = {dependence, polymers, polyelectrolytes, aqueous-solutions, intrinsic viscosities, salt effect, absence, hydrodynamic interactions, isoionic dilution method, isoionic method, neutralized poly(acrylic acid)},
pages = {2786--2790},
}
@article{eckelt_incompatibility_2012,
title = {On {The} {Incompatibility} of {Dextran} and {Pullulan} in {Aqueous} {Solutions} and {Its} {Modeling}},
volume = {213},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000305577800004&action=retrieve&mode=FullRecord},
doi = {10.1002/macp.201200040},
abstract = {Joint aqueous solutions of branched dextran and linear pullulan are investigated with respect to their phase separation. The experiments demonstrate that the polymers are depending on the molar mass of dextran incompatible in aqueous solutions despite their chemical similarity. This finding can be modeled on the basis of an approach accounting for chain connectivity and conformational relaxation of the components. According to these calculations, the polymers exhibit a miscibility gap in joint solutions despite the favorable interactions between them. Using information on the subsystems H2O/dextran and H2O/pullulan, the assumption of complete miscibility of the polysaccharides is required to model the observed phase separation. This analysis predicts the existence of two islands of immiscibility for the ternary system.},
language = {English},
number = {12},
journal = {Macromolecular Chemistry and Physics},
author = {Eckelt, A. and Eckelt, J. and Schartl, W. and Wolf, B. A.},
month = jun,
year = {2012},
keywords = {thermodynamics, fluids, equilibria, interaction parameters, mixtures, derivatives, gibbs energy, copolymer, huggins interaction parameters, chain connectivity, dextran, pullulan, equation-of-state, polysaccharide solutions, ternary phase diagrams},
pages = {1206--1215},
}
@article{eckelt_interpolymer_2012,
title = {Interpolymer {Complexes} and {Polymer} {Compatibility}},
volume = {33},
issn = {1022-1336},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000310964700005&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/marc.201200431},
abstract = {A reliable method to decide whether two polymers A and B are miscible or incompatible would be very helpful in many ways. In this contribution we demonstrate why traditional procedures cannot work. We propose to use the intrinsic viscosities [?] of the polymer blends instead of the composition dependence of the viscosities as a criterion for polymer miscibility. Two macromolecules A and B are miscible because of sufficiently favorable interactions between the two types of polymer segments. For solutions of these polymers in a joint solvent, this Gibbs energetic preference of dissimilar intersegmental contacts should prevail upon dilution and lead to the formation of interpolymer complexes, manifesting themselves in deviations from the additivity of intrinsic viscosities.},
language = {English},
number = {22},
journal = {Macromolecular Rapid Communications},
author = {Eckelt, A. and Eckelt, J. and Wolf, B. A.},
month = nov,
year = {2012},
keywords = {miscibility, viscosity measurements, solvent, polyelectrolytes, mixtures, aqueous-solutions, interpolymer complex, dextran, pullulan, intrinsic viscosity, intrinsic viscosities, polymer compatibility, ternary systems, viscometry},
pages = {1933--1937},
}
@article{nita_synergistic_2013,
title = {Synergistic behavior of poly(aspartic acid) and {Pluronic} {F127} in aqueous solution as studied by viscometry and dynamic light scattering},
volume = {103},
issn = {0927-7765},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000315127000072&action=retrieve&mode=FullRecord},
doi = {10.1016/j.colsurfb.2012.10.054},
abstract = {Pluronic F127/poly(aspartic acid) mixtures were investigated in dilute solutions by viscometry and dynamic light scattering. The two polymers were chosen due to well known applications in biomedical field, taking into account the final purpose (the use of the complex structure as drug delivery systems). The central item was to identify the possibility of complexation between the poly(carboxylic acid) and a non-ionic polymer and to investigate the conditions of the interpolymer complex formation. The ability of Pluronic F127 to form micelle is well known. Poly(aspartic acid), as a polycarboxylic acid with resemblance with polyacrylic acid, can act as dispersant, antiscalant, superabsorber, being also able to form micelles. Due to its functional groups, -COOH and -NH2, poly(aspartic acid) can make physical and/or chemical bonds with other macromolecular compounds. The intrinsic viscosity and the dynamic light scattering data obtained for PLU/PAS mixtures at 25 degrees C have shown that interpolymer complex formation occurs around 1/1 wt. ratio between the two polymers. (C) 2012 Elsevier B.V. All rights reserved.},
journal = {Colloids and Surfaces B-Biointerfaces},
author = {Nita, Loredana E. and Chiriac, Aurica and Bercea, Maria and Wolf, Bernhard A.},
month = mar,
year = {2013},
pages = {544--549},
}
@article{bercea_polyelectrolyte_2012,
title = {Polyelectrolyte {Complexes}: {Phase} {Diagram} and {Intrinsic} {Viscosities} of the {System} {Water}/{Poly}(2-vinylpyridinium-{Br})/{Poly}(styrene sulfonate-{Na})},
volume = {213},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000312656400009&action=retrieve&mode=FullRecord},
doi = {DOI 10.1002/macp.201200445},
abstract = {In contrast to all earlier work on that subject, measurements are performed at high dilution up to total polymer concentrations wpol of 0.5 wt\%. Aqueous solutions of poly(2-vinylpyridinium-Br) and of poly(styrene sulfonate-Na) are only fully miscible if wpol {\textless} 0.02 wt\%. Decomposition into two liquid phases is observed upon an increase in wpol, where the extension of the miscibility gap is considerably larger at 60 than at 25 degrees C. Viscosity measurements demonstrate that the formation of the polyelectrolyte complexes may take hours. The intrinsic viscosity of the polyanion turns out to be 20 times larger than that of the polycation and to be much more sensitive toward the addition of extra salt. The [?] values of the blend pass a minimum as a function of its composition.},
language = {English},
number = {23},
journal = {Macromolecular Chemistry and Physics},
author = {Bercea, M. and Nita, L. E. and Eckelt, J. and Wolf, B. A.},
month = dec,
year = {2012},
keywords = {kinetics, phase diagrams, mechanism, solution properties, intrinsic viscosities, exchange, kinetics of complex formation, linear polyelectrolytes, polyelectrolyte complexes},
pages = {2504--2513},
}
@article{xiong_linear_2012,
title = {Linear versus {Three}-{Arm} {Star} {Polybutadiene}: {Effects} of {Polymer} {Architecture} on the {Thermodynamic} {Solution} {Behavior}},
volume = {45},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000312122600035&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ma302010j},
abstract = {The interaction of linear and of three-arm star polybutadiene (PB) with THF was studied in the temperature range between 25 and 55 degrees C. Information for dilute solution rests on light scattering experiments; Flory-Huggins interaction parameter chi stem from vapor pressure measurements as a function of phi, the volume fraction of polymer. Despite the minute divergence in the architecture, the second osmotic virial coefficients of the two PBs differ noticeably. The present work demonstrates that these disparities become much more pronounced as phi increases and that they depend strongly on temperature. These findings are interpreted on the basis of an approach accounting for the effects of chain connectivity and for conformational changes of the components. In this manner it is possible to rationalize the observed complex dependencies chi (phi, T), and to relate these effects to the dissimilar free volumes of the polymers.},
language = {English},
number = {23},
journal = {Macromolecules},
author = {Xiong, X. P. and Eckelt, J. and Wolf, B. A.},
month = dec,
year = {2012},
keywords = {polystyrene, fractionation, 2nd virial-coefficient},
pages = {9539--9546},
}
@article{wolf_unified_2013,
title = {Unified {Thermodynamic} {Modeling} of {Polymer} {Solutions}: {Polyelectrolytes}, {Proteins}, and {Chain} {Molecules}},
volume = {52},
issn = {0888-5885},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000315937000045&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Ie4000757},
abstract = {The thermodynamic description of the systems specified in the title requires in general dissimilar theories. This contribution presents an approach that is capable of modeling all of them with a maximum of three adjustable parameters. The Ansatz starts from the Flory-Huggins theory and extends it in a 2-fold manner: The number of segments assigned to the solvent is no longer one but treated as an adjustable parameter to account for the differences in the molecular geometries and in the free volumes of the components. Furthermore, the modeling allows for effects resulting from ternary contacts of the solvent/polymer/polymer type. Examination of the acquired thermodynamic expressions by means of literature data (composition-dependent chemical potentials of the solvents) demonstrates their validity. Solutions of proteins and of linear or branched chainlike macromolecules require two adjustable parameters for the quantitative thermodynamic modeling; polyelectrolyte solutions necessitate a third one.},
language = {English},
number = {9},
journal = {Industrial \& Engineering Chemistry Research},
author = {Wolf, B. A.},
month = mar,
year = {2013},
keywords = {water, aqueous-solutions, sorption},
pages = {3530--3536},
}
@article{antonov_liquidgas_2013,
title = {Liquid/{Gas} and {Liquid}/{Liquid} {Phase} {Equilibria} of the {System} {Water}/{Bovine} {Serum} {Albumin}},
volume = {117},
issn = {1520-6106},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000318891700010&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Jp4010482},
abstract = {The thermodynamic behavior of the system H2O/BSA was studied at 25 degrees C within the entire composition range: vapor pressure measurements via head space sampling gas chromatography demonstrate that the attainment of equilibria takes more than one week. A miscibility gap was detected via turbidity and the coexisting phases were analyzed. At 6 degrees C the two phase region extends from ca. 34 to 40 wt 96 BSA; it shrinks upon heating. The polymer rich phase is locally ordered, as can be seen under the optical microscope using crossed polarizers. The Flory-Huggins theory turns out to be inappropriate for the modeling of experimental results. A phenomenological expression is employed which uses three adjustable parameters and describes the vapor pressures quantitatively; it also forecasts the existence of a miscibility gap.},
language = {English},
number = {18},
journal = {Journal of Physical Chemistry B},
author = {Antonov, Y. and Eckelt, J. and Sugaya, R. and Wolf, B. A.},
month = may,
year = {2013},
keywords = {kinetics, interaction parameters, mechanism, complexes, exchange, proteins},
pages = {5497--5502},
}
@article{xiong_intrinsic_2014,
title = {Intrinsic viscosities of polyelectrolytes: specific salt effects and viscometric master curves},
volume = {10},
issn = {1744-683X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000332478800005&action=retrieve&mode=FullRecord},
doi = {Doi 10.1039/C3sm52295d},
abstract = {Dilute solutions of the sodium salt of polystyrene sulfonic acid (PSS-Na) were measured viscometrically as a function of composition in aqueous solvents of different salinity, where the extra salt was either NaCl or CaCl2. Such experiments yield {eta}, the generalized intrinsic viscosities (hydrodynamic specific volume) of the polyelectrolyte for arbitrary polymer concentrations, c. In the limit of infinite dilution {eta} becomes identical to the intrinsic viscosity [eta]. For NaCl {eta} decreases monotonously with rising c, whereas maxima are passed in the case of CaCl2. Condensing c and the concentration of extra salt in the mixed solvent into a single variable enables the establishment of predictive master curves. The viscometrically observed changes in the spatial extension of the individual polymer coils are discussed in light of the corresponding thermodynamic information.},
language = {English},
number = {13},
journal = {Soft Matter},
author = {Xiong, X. P. and Wolf, B. A.},
year = {2014},
keywords = {phase-diagram, dilute-solutions, absence, aqueous-solution, binding, condensation, ions, multivalent salts, precipitation},
pages = {2124--2131},
}
@article{antonov_joint_2014,
title = {Joint {Aqueous} {Solutions} of {Dextran} and {Bovine} {Serum} {Albumin}: {Coexistence} of {Three} {Liquid} {Phases}},
volume = {30},
issn = {0743-7463},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000337198900024&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/La501419e},
abstract = {The phase diagram of the system water/dextran (DEX)/BSA was measured as well as modeled. On the experimental side, cloud points were determined and the coexisting phases were analyzed. The theoretical calculations use an approach capable of describing solutions of chain polymers and of globular proteins with the same formalism. The required thermodynamic 'input comes from experiments concerning the binary subsystems, except for the polymer blend for which one-interaction parameter had to be adjusted. Both sources of information yield the same essential features: the existence.. of a large composition area of immiscibility, starting from the subsystem DEX/BSA and extending well into the region of dilute polymer solutions. This range is subdivided into three sections: one two-phase area at high polymer content, a two-phase area at low polymer content, and a three-phase region located in between. Measured and calculated phase diagrams match qualitatively; the reasons for the quantitative discrepancies are being discussed.},
language = {English},
number = {22},
journal = {Langmuir},
author = {Antonov, Y. and Wolf, B. A.},
month = jun,
year = {2014},
keywords = {behavior, thermodynamics, equilibria, mixtures, separation, polysaccharides, proteins, 2-phase systems, glycobiology},
pages = {6508--6515},
}
@article{bercea_thermodynamics_2014,
title = {Thermodynamics of {Copolymer} {Solutions}: {How} the {Pair} {Interactions} {Contribute} to the {Overall} {Effect}},
volume = {118},
issn = {1520-6106},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000340223000032&action=retrieve&mode=FullRecord},
doi = {Doi 10.1021/Jp505155e},
abstract = {Vapor pressure measurements were performed for solutions of poly(methyl methacrylate-ran-tert-butyl methacrylate) with different weight fractions of tert-butyl methacrylate units, and their parental homopolymers in chloroform at 323 K, over a large domain of concentrations. The Flory-Huggins interaction parameters obtained from these experimental investigations show complex dependences of the Flory-Huggins interaction parameter on concentration and copolymer composition. This behavior can be modeled by taking into account an approach which considers the ability of the polymers to rearrange in a response to changes in their molecular surroundings [Adv. Polym. Sri. 2011, 238, 1-66]. According to this concept, the mixing process is subdivided into two clearly separable steps and accounts for the specific interactions between the solvent and copolymer segments.},
language = {English},
number = {31},
journal = {Journal of Physical Chemistry B},
author = {Bercea, M. and Wolf, B. A.},
month = aug,
year = {2014},
keywords = {polystyrene, mixtures, solvent quality, composition dependence, conformational variability, chain connectivity, dilute-solutions, molecular-weight polymers, pressures, vapor-liquid-equilibria},
pages = {9414--9419},
}
@article{antonov_inducing_2015,
title = {Inducing mixing of water-in water {BSA}/dextran emulsion by a strong polyelectrolyte},
volume = {43},
issn = {0268-005X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000345683500030&action=retrieve&mode=FullRecord},
doi = {DOI 10.1016/j.foodhyd.2014.05.029},
abstract = {We examine whether a small amount of strong polyelectrolyte (dextran sulfate sodium salt/DSS/)can induce mixing in water-in-water bovine serum albumin/dextran (BSA/DEX) emulsion and how inter-macromolecular interactions affect its the rheological properties. Addition of DSS to water-in-water emulsion at pH 5.4 leads to its mixing at the DSS/BSA weight ratio, (q(DSS/BSA)) {\textgreater}= 0.07, a noticeable increase in viscosity and storage modulus (G'). Mixing is reversible: increasing the ionic strength leads to phase separation in the water/BSA/DEX/DSS system. The increase in viscoelasticity results from the interaction of DSS with both macromolecular compounds of the emulsion. We assume that similar to compatibilization of polymer blends by diblock copolymers, the driving force for DSS induced mixing of water/BSA/DEX emulsion is the affinity of DSS to both macromolecular compounds of the emulsion. (C) 2014 Elsevier Ltd. All rights reserved.},
language = {English},
journal = {Food Hydrocolloids},
author = {Antonov, Y. A. and Wolf, B. A. and Moldenaers, P.},
month = jan,
year = {2015},
keywords = {behavior, rheology, compatibility, mixtures, separation, polysaccharides, dextran, charged polyelectrolytes, protein, phase-equilibria, bovine serum-albumin, bsa, dextran sulfate, interaction, mixing, polymer systems},
pages = {243--251},
}
@article{bercea_dependence_2015,
title = {Dependence of solvent quality on the composition of copolymers: experiment and theory for solutions of {P}({MMA}-ran-t-{BMA}) in toluene and in chloroform},
volume = {11},
issn = {1744-683X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000346911600020&action=retrieve&mode=FullRecord},
doi = {Doi 10.1039/C4sm02568g},
abstract = {The interaction of toluene with P(MMA-ran-t-BMA) and with the corresponding homopolymers was determined via vapor pressure measurements at 30, 50 and 70 degrees C. A unified thermodynamic approach served for the modeling of the results. It is capable of describing the behavior of the different solutions by means of two adjustable parameters, one representing the effective number of solvent segments and the other accounting for the interactions between the components. The solvent quality of toluene passes a maximum, a minimum and another maximum upon an increase of the t-BMA content of the copolymer at all temperatures. A similar behavior is discernable from vapor pressure data of chloroform published for the same copolymers. The heats of mixing for toluene depend strongly on temperature; at 50 degrees C they are all endothermal with the exception of PMMA, for which the value obtained from vapor pressures at 30 degrees C agrees very well with published caloric data.},
language = {English},
number = {3},
journal = {Soft Matter},
author = {Bercea, M. and Wolf, B. A.},
year = {2015},
keywords = {polymer-solutions, miscibility, systems, interaction parameters, mixtures, conformational variability, adequate thermodynamic description, chain connectivity, methacrylate), of-state analysis},
pages = {615--621},
}
@article{suresha_polyelectrolytes_2015,
title = {Polyelectrolytes in dilute solution: viscometric access to coil dimensions and salt effects},
volume = {5},
issn = {2046-2069},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000351556100059&action=retrieve&mode=FullRecord},
doi = {Doi 10.1039/C5ra01376c},
abstract = {Copolymers of acrylamide (AM) and diallyldimethylammonium chloride (DADMAC), differing in molar masses M (52.3 to 227 kDa) and degrees of charging y (0.2 to 0.6), were studied with respect to their viscometric behavior in dilute aqueous solutions containing variable amounts of NaCl. Complementary measurements were performed on a Brookhaven 90 plus particle size analyzer. M dominates the intrinsic viscosities [eta]. For the viscometric interaction parameters B this is only true for large concentrations of extra salt. [eta] and B as a function of solvent salinity follow Boltzmann laws. Coil dimensions, determined either via dynamic light scattering or viscometry, agree well. For low salt contents of the solvent the radii decrease with rising polymer concentration, whereas they increase for high salt concentrations; at a characteristic salinity of the solvent they become independent. Zeta potentials grow from +20 to +40 mV as y goes up.},
language = {English},
number = {35},
journal = {RSC Advances},
author = {Suresha, P. R. and Badiger, M. V. and Wolf, B. A.},
year = {2015},
keywords = {dependence, behavior, molecular-weight, intrinsic viscosities, aqueous-solution, flocculation, mixed-solvent media, papermaking, radii, retention},
pages = {27674--27681},
}
@article{wolf_viscosity_2015,
title = {Viscosity of {Polymer} {Solutions} over the {Full} {Range} of {Composition}: {A} {Thermodynamically} {Inspired} {Two}-{Parameter} {Approach}},
volume = {54},
issn = {0888-5885},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000353931200069&action=retrieve&mode=FullRecord},
doi = {10.1021/acs.iecr.5b00845},
abstract = {The approach yields the following relation. for the relative viscosity eta(rel) as a function of polymer concentration c (mass/volume): In eta(rel) = (c) over tilde/(1 + p (c) over tilde + q (c) over tilde (2)). Reduced concentrations (c) over tilde (defined as (c) over tilde = c[eta], where [eta] is the intrinsic viscosity) are used instead of c to incorporate thermodynamic information. The parameters p and q account for changes in the free volume of the solvent caused by the polymer. The analysis of literature data for seven very dissimilar systems discloses the following common feature: p {\textgreater} 0 and q {\textless} 0. This means that the curves in the plots of In eta(rel) as a function of {\textless}(c)over tilde{\textgreater} are normally located below the tangent at low (c) over tilde and above it at high (c) over tilde. The Amines of p and q correlate strongly with the temperature distance to the glass-transition temperature of the polymer (T-g). Beyond the Mere modeling of viscosity data, the approach allows the determination of [eta] from data at high polymer concentrations and provides information on the generalized intrinsic viscosity, {eta}. Measurements for T {\textless} T-g give access to glass curves, i.e to T-g(c). Moreover,, the modeling helps to recognize systems with special behavior,, such as solutions of poly(dimethyl siloxane) in its oligomers.},
number = {16},
journal = {Industrial \& Engineering Chemistry Research},
author = {Wolf, Bernhard A.},
month = apr,
year = {2015},
pages = {4672--4680},
}
@article{nita_self-assembling_2017,
title = {Self-assembling of poly(aspartic acid) with bovine serum albumin in aqueous solutions},
volume = {95},
issn = {0141-8130},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000392903000053&action=retrieve&mode=FullRecord},
doi = {10.1016/j.ijbiomac.2016.11.080},
abstract = {Macromolecular co-assemblies built up in aqueous solutions, by using a linear polypeptide, poly(aspartic acid) (PAS), and a globular protein, bovine serum albumin (BSA), have been studied. The main interest was to identify the optimum conditions for an interpenetrated complex formation in order to design materials suitable for biomedical applications, such as drug delivery systems. BSA surface possesses several amino- and carboxylic groups available for covalent modification, and/or bioactive substances attachment. In the present study, mixtures between PAS and BSA were investigated at 37 degrees C in dilute aqueous solution by viscometry, dynamic light scattering and zeta potential determination, as well as in solid state by AFM microscopy and dielectric spectroscopy. The experimental data have shown that the interpolymer complex formation occurs for a PAS/BSA molar ratio around 0.541. (C) 2016 Elsevier B.V. All rights reserved.},
language = {English},
journal = {International Journal of Biological Macromolecules},
author = {Nita, L. E. and Chiriac, A. P. and Bercea, M. and Asandulesa, M. and Wolf, B. A.},
month = feb,
year = {2017},
keywords = {temperature, polyelectrolytes, interpolymer complex, intrinsic viscosities, proteins, bovine serum albumin, complexation, dynamic light-scattering, nanoparticles, ph, pluronic f127, poly(aspartic acid), poly(vinyl alcohol sulfate), self-assembling},
pages = {412--420},
}
@article{wolf_coil_2016,
title = {Coil overlap in moderately concentrated polyelectrolyte solutions: effects of self-shielding as compared with salt-shielding as a function of chain length},
volume = {6},
issn = {2046-2069},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000374495400064&action=retrieve&mode=FullRecord},
doi = {10.1039/c6ra04488c},
abstract = {The generalized intrinsic viscosity {eta} (hydrodynamic volume of the solute at arbitrary polymer concentration c) -introduced by analogy to the intrinsic viscosity [eta] - provides access to the degree of coil overlap Omega for polyelectrolyte solutions in pure water or in saline water. The experimental basis of this investigation consists in viscosity measurements as a function of c for a large number of sodium polystyrene sulfonate (Na-PSS) samples covering the molecular weight range from 0.91 to 1000 kg mol(-1). The accurate modeling of these dependencies with a maximum of three parameters yields detailed information on Omega as a function of (c) over tilde (c[eta]) in the absence and in the presence of extra salt. It demonstrates that the polymer character of PSS-Na is lost as the number of monomeric units falls below approximately 15. In the case of pure water the extent of coil overlap resulting at given (c) over tilde grows markedly with rising M. The minimum share of self-shielding in the total shielding - resulting for a large surplus of extra salt - depends on Omega. It starts from zero at infinite dilution and approaches limiting values on the order of 90\% in all cases. The transition between these two values spreads out over increasing ranges of Omega as M becomes larger. Also discussed are generalized Kuhn-Mark-Houwink relations for constant c and unexpected concentration dependencies of Omega.},
number = {44},
journal = {RSC Advances},
author = {Wolf, Bernhard A.},
year = {2016},
pages = {38004--38011},
}
@article{bercea_consequences_2017,
title = {Consequences of linking charged and uncharged monomers to binary copolymers studied in dilute solution. {Part} {I}: {Viscometric} behavior of the homopolymers, the effects of charging, and uncommon salt effects},
volume = {88},
issn = {0014-3057},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000396952500035&action=retrieve&mode=FullRecord},
doi = {10.1016/j.eurpolymj.2016.12.008},
abstract = {Intrinsic viscosities, generalized intrinsic viscosities and viscometric interaction parameters were measured for aqueous solutions of poly(ethylene oxide) [PEO poly(N,Ndimethyl aminoethyl methacrylate) [PR] (uncharged) and for poly{[2-(methacryloyloxy)e thyl] trimethylammonium iodide} [PR+] (charged) within a wide range of molar masses. In this manner it was possible to establish the information required for the study of non-additivity effects upon the formation of binary copolymers from the monomers specified above. The following additional items were of particular interest: The effects of charging PR to PR+. and the composition dependence of the coil overlap in the case of saline (NaCI, CaCl2 and Nal) solvents. NaCI turned out to be much less efficient in shielding the electrostatic interactions than the other salts due to its large tendency to form ion pairs in solution. (C) 2016 Elsevier Ltd. All rights reserved.},
language = {English},
journal = {European Polymer Journal},
author = {Bercea, M. and Morariu, S. and Wolf, B. A.},
month = mar,
year = {2017},
keywords = {viscosity, light-scattering, aqueous-solutions, intrinsic viscosity, kuhn-mark-houwink relation, salt effect, ph, aqueous solution, coil overlap, poly(n,n-dimethylaminoethyl methacrylate), weak polyelectrolytes},
pages = {412--421},
}
@article{bercea_consequences_2017-1,
title = {Consequences of linking charged and uncharged monomers to binary copolymers studied in dilute solution. {Part} {II}: {Non}-additivity effects in the viscometric behavior},
volume = {88},
issn = {0014-3057},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000396952500036&action=retrieve&mode=FullRecord},
doi = {10.1016/j.eurpolymj.2016.12.007},
abstract = {Copolymers of ethylene oxide (EO) and N,N-dimethyl aminoethyl methacrylate (R) or [2(methacryloyloxy)ethyl] trimethylammonium iodide (R+) were studied in dilute solution: P(EOp -b -R-n)(I), P(Rn(1-f) - ran - R-n(+) (f) ).(II), and P(EOP - b - R-n(+))(III); n and p give the numbers of monomers and f is the degree of charging. For II (variable)) and III (variable n) the effects of charging on the intrinsic viscosities [n] are well described by Boltzmann sigmoids. The deviation of [n] from n (calculated from the corresponding homopolymer data, assuming additivity of the individual contributions) are quantified by sigma =[n]/n -1 measuring the segregation (sigma {\textgreater} 0) or clustering (sigma {\textless} 0) of dissimilar monomers in isolated coils. For II, changes from negative at low f to positive at high) I and III pass maxima as n becomes larger, where a is positive at low and negative at high n for I, but always larger than zero for III. The investigation of salt effects using NaCl, CaCl2 and Nal corroborates the observations for the homopolymers. (C) 2016 Elsevier Ltd. All rights reserved.},
language = {English},
journal = {European Polymer Journal},
author = {Bercea, M. and Wolf, B. A.},
month = mar,
year = {2017},
keywords = {viscosity, polyelectrolytes, mixtures, intrinsic viscosity, polymer architecture, complexes, aqueous solution, charged block copolymers, DNA, extra salt effect, gene delivery-systems, methacrylate, peg},
pages = {422--432},
}
@article{xiong_versatile_2017,
title = {A versatile viscometric method for the study of dissolved proteins, exemplified for casein micelles in ammoniacal solutions},
volume = {72},
issn = {0268-005X},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000405985200020&action=retrieve&mode=FullRecord},
doi = {10.1016/j.foodhyd.2017.05.034},
abstract = {Viscosities of casein solutions were measured within the dilute range in ammoniacal water and in saline solvents containing different amounts and different kinds of salt. All these data are modeled quantitatively by means of an approach accounting for the polyelectrolyte character of casein micelles. Two parameters are required: The intrinsic viscosity [eta] and a viscometric interaction parameter beta. The behavior of casein is compared with that of chain-like polyelectrolytes. For both polymers one observes a pronounced reduction of [eta] with increasing salt concentration. However, for casein the decline of [eta] is less pronounced by more than an order of magnitude and depends on the chemical nature of the salt. In the case of low solvent salinities, the beta values are in both cases positive (less than exponential increase of the viscosity with rising solute concentration). However, for casein beta changes from positive to negative (more than exponential increase) with rising salt concentration. Reasons for the dissimilarities between the two types of polyelectrolytes are discussed. (C) 2017 Elsevier Ltd. All rights reserved.},
journal = {Food Hydrocolloids},
author = {Xiong, Xiaopeng and Huang, Xuejiao and Wolf, B. A.},
month = nov,
year = {2017},
pages = {195--201},
}
@article{bercea_viscometry_2017,
title = {Viscometry of polyelectrolyte solutions: {Star}-like versus linear poly 2-(methacryloyloxy)ethyl trimethylammonium iodide and specific salt effects},
volume = {93},
issn = {0014-3057},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000407186200015&action=retrieve&mode=FullRecord},
doi = {10.1016/j.eurpolymj.2017.05.040},
abstract = {The intrinsic viscosities, [a], of the 3-arm star polyelectrolyte in pure water are for a given molar mass considerably lower than for the linear product because of the higher monomer concentration and charge density in isolated coils. These effects are much more pronounced than in the case of uncharged macromolecules. Extra salt (NaCI, NaI, CaCl2) reduces the solution viscosities of the 3-arm star polymer less than of the linear product. The transition of [eta] from the value in pure water to the minimum saturation value at high salt concentrations follows a Boltzmann sigmoid. In saline solvents the changes of the viscosities with rising polymer concentration depend strongly on the chemical nature of the salt and on the molecular architecture of the solute. The present findings demonstrate the necessity to account for thermodynamic interactions between all components of the mixture, in addition to the usual electrostatic considerations. These considerations should turn out helpful for a better understanding of salt induced topological transitions of charged biopolymers.},
journal = {European Polymer Journal},
author = {Bercea, M. and Wolf, B. A.},
month = aug,
year = {2017},
pages = {148--157},
}
@article{tuting_potassium_2017,
title = {Potassium {Triggers} a {Reversible} {Specific} {Stiffness} {Transition} of {Polyethylene} {Glycol}},
volume = {121},
issn = {1932-7447},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000413131700068&action=retrieve&mode=FullRecord},
doi = {10.1021/acs.jpcc.7b08987},
abstract = {We use plasmon rulers made from two connected gold nanoparticles to monitor the conformation and stiffness of single PEG molecules and their response to cations. By observing equilibrium fluctuations of the interparticle distance, we obtain the spring constants or stiffness of the connecting single-molecule tether with pico-Newton sensitivity. We observe a transition of the PEG molecules' extension and stiffness above about 1.2 mM K+ ion concentration which is specific to potassium ions. Molecular dynamics simulations reveal the formation of crown-like structures as the most likely molecular mechanism responsible for this specific effect.},
number = {40},
journal = {Journal of Physical Chemistry C},
author = {Tüting, L. and Ye, W. X. and Settanni, G. and Schmid, F. and Wolf, B. A. and Ahijado-Guzman, R. and Sönnichsen, C.},
month = oct,
year = {2017},
pages = {22396--22402},
}
@article{wolf_intrinsic_2018,
title = {Intrinsic {Viscosities} of {Polymer} {Blends} and {Polymer} {Compatibility}: {Self}-{Organization} and {Flory}-{Huggins} {Interaction} {Parameters}},
volume = {219},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000444956500010&action=retrieve&mode=FullRecord},
doi = {10.1002/macp.201800249},
abstract = {The intrinsic viscosity of polymer blends in a common solvent may deviate markedly from additivity. Such behavior testifies favorable interactions between the two types of macromolecules. Under these conditions, isolated polymer coils contain one macromolecule of each species and represent the simplest possible case of self-organization. The particular thermodynamic situation required for the occurrence of that phenomenon is being analyzed in terms of microphase equilibria by means of an approach, which subdivides the dilution process into two steps. The first step quantifies the opening of intersegmental contacts at constant conformations of the components and the second step the conformational relaxation required to attain equilibrium. The intrinsic viscosities resulting for the mixed isolated coils are normally smaller than calculated from additivity. However, the opposite behavior can also occur under special conditions. The possibilities to gain quantitative information on polymer/polymer interaction parameters from the intrinsic viscosities of polymer blends are being discussed.},
language = {English},
number = {18},
journal = {Macromolecular Chemistry and Physics},
author = {Wolf, B. A.},
month = sep,
year = {2018},
keywords = {miscibility, polymer blends, thermodynamics, mixtures, phase-behavior, intrinsic viscosities, polymer compatibility, coils, Flory-Huggins interaction parameters, isolated, polystyrene-polybutadiene-chloroform, self-organization},
}
@article{bercea_intrinsic_2018,
title = {Intrinsic {Viscosities} of {Polymer} {Blends}: {Sensitive} {Probes} of {Specific} {Interactions} between the {Counterions} of {Polyelectrolytes} and {Uncharged} {Macromolecules}},
volume = {51},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000447238900006&action=retrieve&mode=FullRecord},
doi = {10.1021/acs.macromol.8b01422},
abstract = {In joint dilute aqueous solutions of pullulan (PUL) and poly(sodium 4-styrenesulfonate) (PSS-Na) the Na+ ions of the polyelectrolyte interact so favorably with the monomeric units of PUL that isolated coils containing both types of macromolecules are formed upon dilution. When water is replaced against a 1 M solution of NaCl, this effect dies out because of the large surplus of Na+ ions. On the other hand, if the water contains increasing amounts of the respective counterpolymer instead of NaCl, the formation of mixed isolated coils is fostered, where a further diminution of the intrinsic viscosities is caused by the lower the solvent quality. The molar mass of PSS-Na plays an important role for the viscosities of the solutions in pure water. The reason lies in the different extent of the electrostatic self-shielding as a function of the polyelectrolyte concentration.},
language = {English},
number = {19},
journal = {Macromolecules},
author = {Bercea, M. and Wolf, B. A.},
month = oct,
year = {2018},
keywords = {behavior, compatibility, mixtures, complexes, salt, sodium polystyrene sulfonate},
pages = {7483--7490},
}
@article{sadadi_concentration-dependent_2019,
title = {Concentration-dependent switch between chain association and dissociation of oppositely charged weak polyelectrolytes in solution},
volume = {172},
issn = {0032-3861},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000466806100021&action=retrieve&mode=FullRecord},
doi = {10.1016/j.polymer.2019.03.065},
abstract = {Joint solutions of oppositely charged weak polyelectrolytes are considerably less studied than their strong counterparts; as a result, their thermodynamic understanding is still unsatisfactory. This shortcoming hampers the development of a general picture about the physical properties of these mixtures, which further hampers their use to design new materials. To close this gap, we investigate the ternary system ethanol/polyacid/polybase (polyacid: methacrylic acid containing copolymer; polybase: N,N-dimethylaminoethyl methacrylate containing terpolyrner) with respect to its demixing and viscometric behavior. Complete homogeneity can only be reached if the total polymer concentration remains below 0.005 g dL(-1). The locations of the fie lines in the phase diagram reveal that the interpolymer contacts are favorable at low polymer concentrations but unfavorable at high concentrations; viscosity measurements corroborate these findings. Adding either acid or base to the solvent extends the region of homogeneity, where low concentrations of HCl split the two-phase region into two separate parts. This phenomenon is rationalized in terms of concentration-dependent changes in the degree of ionization of the polybase.},
journal = {Polymer},
author = {Sadadi, H. and Imani, M. and Atai, M. and Wolf, B. A. and Seiffert, S.},
month = may,
year = {2019},
pages = {178--186},
}
@article{wolf_extension_2019,
title = {Extension of the {Concept} of {Intrinsic} {Viscosities} to {Arbitrary} {Polymer} {Concentration}: {From} eta via {eta} to {Intrinsic} {Bulkiness}},
volume = {52},
issn = {0024-9297},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000468243100009&action=retrieve&mode=FullRecord},
doi = {10.1021/acs.macromol.9b00282},
abstract = {The capabilities of an alternative definition of intrinsic viscosities [eta] published some years ago is being studied by means of comprehensive viscometric data reported in the early days of polymer science. It introduces the generalized intrinsic viscosity {eta} as the specific hydrodynamic volume at arbitrary polymer concentration c. {eta} quantifies the size of the flow unit and decreases monotonously for T {\textgreater}{\textgreater} T-g (glass transition temperature) as a function of c but passes a pronounced minimum as T approaches T-g. In the limit of the pure polymer melt, {eta} becomes [eta]; this newly introduced property is termed intrinsic bulkiness, by analogy to the intrinsic viscosity, and provides noncalorimetric experimental access to T-g; it also allows estimates of entanglement molecular weights based on the Newtonian flow behavior. Moreover, the molecular weight dependence of [eta] provides information on the contributions of endgroups to the flow behavior.},
number = {9},
journal = {Macromolecules},
author = {Wolf, B. A.},
month = may,
year = {2019},
pages = {3231--3236},
}
@article{bercea_associative_2019,
title = {Associative behaviour of kappa-carrageenan in aqueous solutions and its modification by different monovalent salts as reflected by viscometric parameters},
volume = {140},
issn = {0141-8130},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000501656200072&action=retrieve&mode=FullRecord},
doi = {10.1016/j.ijbiomac.2019.08.144},
abstract = {The viscometric behaviour of kappa-carrageenan in aqueous solutions and in the presence of monovalent salts was investigated at 25 degrees C. Coil, helix or double helix conformations were induced by cooling hot kappa-carrageenan solutions under appropriate ionic conditions. A new viscometric approach was used for modeling the behaviour of kappa-carrageenan solutions. The intrinsic viscosity, [eta], is markedly changed by the presence of different monovalent salts (NaCl, NaI and CsI). In pure water, the intrinsic viscosity amounts to 48 dL.g(-1). In 0.1 M NaCl solutions (single helix state) [eta] is 6.2 whereas in 0.1 M NaI (double helix conformation) it is approximately twice as large. In 0.1 M CsI (dissimilar cation and counter-ion) the intrinsic viscosity is three times larger, suggesting the formation of the associated kappa-carrageenan helices. Stepwise association of kappa-carrageenan helices was followed in presence of NaI/CsI mixtures of different compositions. The value of Smidsred-Haug stiffness parameter (B) measured for kappa-carrageenan in NaCl solutions is 4.47 x 10(-2), higher than that of DNA (5.5 x 10(-3)), but lower than those reported for carboxymethyl cellulose (6.3 x 10(-2)), indicating that the chain conformation is moderately rigid. (C) 2019 Elsevier B.V. All rights reserved.},
language = {English},
journal = {International Journal of Biological Macromolecules},
author = {Bercea, M. and Wolf, B. A.},
month = nov,
year = {2019},
keywords = {dependence, viscosity, polyelectrolytes, transition, mechanism, Association, chain, conformation, Conformation, counterions, helices, Intermolecular interactions, Intrinsic viscosity, kappa-Carrageenan, Monovalent salt, stiffness},
pages = {661--667},
}
@article{wolf_shear_2020,
title = {Shear {Thinning}: {Determination} of {Zero}-{Shear} {Viscosities} from {Measurements} in the {Non}-{Newtonian} {Region}},
volume = {221},
issn = {1022-1352},
url = {https://apps.webofknowledge.com/InboundService.do?product=WOS&UT=000544094200001&action=retrieve&mode=FullRecord},
doi = {10.1002/macp.202000130},
abstract = {Experimental information on the viscosities, eta, of polymer solutions and of polymer melts as a function of shear rate is modeled by means of an approach that describes the diminution of ln eta as a function of shear stress, tau, in terms of an exponential decay. The approach uses the following three adjustable parameters: the zero-shear viscosity of the system, a characteristic shear stress, quantifying its susceptibility toward shear thinning, and a dimensionless parameter stating the magnitude of the effect. This procedure gives access to the Newtonian behavior also in cases where direct measurements are impractical or impossible; it discloses two phenomena not reported so far: a qualitative change in the efficacy of tau at a characteristic concentration and indicates the occurrence of two different disentanglement mechanisms in thermodynamically unfavorable solvents.},
language = {English},
number = {14},
journal = {Macromolecular Chemistry and Physics},
author = {Wolf, B. A.},
month = jul,
year = {2020},
keywords = {polymer solutions, shear, polymer melts, zero shear viscosity, rheology, molecular-weight, curves, modeling shear thinning, polydimethylsiloxanes, thinning},
}
@article{bercea_detection_2021,
title = {Detection of polymer compatibility by means of self-organization: poly(ethylene oxide) and poly(sodium 4-styrenesulfonate)},
volume = {17},
issn = {1744-683X},
doi = {10.1039/d1sm00170a},
abstract = {Information on the miscibility of different polymers A and B on a molecular level is important in many ways. However, along the traditional lines this knowledge is difficult and time consuming to achieve. The current study presents a simple alternative, based on the determination of the intrinsic viscosities (specific hydrodynamic volume of isolated coils) for blend solutions in a common solvent. In the case of incompatible polymers, isolated coils contain one macromolecule only, either A or B. In contrast, compatible polymers form mixed isolated coils, because of favorable interactions. The present investigation was carried out for the system water/poly(ethylene oxide)/poly(sodium 4-polystyrenesulfonate), for which the reason of compatibility lies in the formation Na+ bridges between the sulfonate groups of the polyelectrolyte and the OH groups of the poly(ethylene oxide). Zero shear viscosities were measured as a function of polymer concentration for blends of different compositions and modeled quantitatively by means of relations yielding the excess intrinsic viscosities epsilon (zero in the case of incompatibility) and viscometric interaction parameters. Particular attention is being paid to the role the molar masses of the polymers play for the resulting epsilon values.},
journal = {Soft Matter},
author = {Bercea, M. and Wolf, B. A.},
year = {2021},
pages = {5214--5220},
}
@article{wolf_polymer_2021,
title = {Polymer solutions: {Equilibrium} clusters versus shear clusters},
volume = {212},
issn = {0032-3861},
doi = {10.1016/j.polymer.2020.123149},
abstract = {Polymer solutions are inhomogeneous on mesoscopic scales as a result of chemical bonds linking their monomeric units. This situation leads to polymer clusters within which the polymer concentration c(cluster), is only a small fraction of the overall concentration c. The ratio c/c(cluster) (overlap parameters Omega) quantifies the number of clusters that need to overlap to yield c. Equilibrium clusters (minimization of Gibbs energy) and shear clusters (minimization of entropy production) differ fundamentally where Omega(equ)(il) {\textgreater}= Omega(sh)(ear). Only in the vicinity of the glass transition temperature and at high concentration the opposite is the case. Experimental information on Omega(equ)(il) as a function of phi, the volume fraction of polymer, yields coil-overlap and cross-over concentrations in agreement with the results of scattering studies; analogous information on Omega(s)(hear) (phi) gives access to cross-over concentrations under shear. Theoretical aspects and questions of practical interest arising from the observed differences between equilibrium and shear clusters are being discussed.},
journal = {Polymer},
author = {Wolf, B. A.},
month = jan,
year = {2021},
}
@article{wolf_solutions_2022,
title = {Solutions of polymer blends in highly saline water: {Salt}-induced inversions of viscosity effects for poly(ethylene oxide) + poly(sodium 4-styrenesulfonate)},
volume = {241},
abstract = {Solution viscosities were measured for an uncharged polymer [poly(ethylene oxide): PEO], for a polyelectrolyte
[poly(sodium 4-styrenesulfonate): PSS-Na] and for the blends of these components in water of variable salinities.
The evaluation of these data with respect to the intrinsic viscosities revealed the following: for NaCl as extra salt,
the intrinsic viscosities of the blends are always less than predicted by additivity; moreover the [η] values of PEO
increase with rising salinity of the solvent, in contrast to that of PSS-Na which decrease. This situation leads to an
inversion point of the salt effects at the salinity of approximately 2.9 mol/L. This finding becomes comprehensible
by treating the salt solutions as mixed solvents. Replacing NaCl by the CaCl2 (divalent cation) as extra
salt leads to the [η] values for the blends, which are larger than additive. Based on phenomenological thermodynamic
consideration this behavior is attributed to an entropy driven formation of interpolymer complexes and
explained in molecular terms.},
journal = {Polymer},
author = {Wolf, B. A.},
year = {2022},
keywords = {Blends of charged and uncharged polymers, Inversion of salt effects, Polymer compatibility, Saline solvents, Viscosity of blend solutions},
pages = {124--510}
}
@article{wolf_why_2022,
title = {Why saline water must be treated as a mixed solvent, demonstrated for casein solutions.},
volume = {647},
abstract = {The flow of the casein solutions changes profoundly with the salinity m of the solvent at a critical value m Ξ. Pure
water is – according to intrinsic viscosities – the best solvent. Up to a NaCl concentration of m Ξ = 0.05 mol/L the
solvent quality decreases rapidly, beyond this value the deterioration continues, but at much more lower rate.
The characteristic parameter m Ξ plays a decisive role for the concentration dependence of the generalized
intrinsic viscosity {η} (specific hydrodynamic volume of casein at a certain concentration c) and for the concentration
dependence of the overlap parameter Ω, quantifying the number of solute molecules flowing
conjointly. For m {\textless} m Ξ the generalized intrinsic viscosity decreases with rising c, whereas the opposite is the case
for m {\textgreater} m Ξ. At the critical salinity m Ξ the system adopts a unique behavior: {η} becomes independent of
composition, which means that Ω increases linearly with rising c. This observation is not limited to casein, but
also applies to solutions of polycations and of polyanions. The observed far reaching consequences of the prevailing
solvent salinity can be rationalized in terms of distinct differences in the interaction between the charged
solute on one side and the mixture of hydrated ions plus ion pairs existing in the saline solvent on the other side.},
journal = {Colloids and Surfaces A},
author = {Wolf, B. A.},
year = {2022},
keywords = {Fundamental change in flow at a characteristic, Generalized intrinsic viscosity vs. salinity, Intrinsic viscosity vs. salinity, Jamming concentration vs. salinity, Modeling the viscosity of casein solutions in, saline water, salt concentration, Treating saline water as a mixed solvent},
}
@article{bercea_rheology_2024,
title = {Rheology of aqueous solutions of brea gum: {Bimodal} flow curves and (apparent) negative activation energies},
volume = {146},
issn = {0268-005X},
journal = {Food Hydrocolloids},
author = {Bercea, Maria and Masuelli, Martin A. and Wolf, Bernhard A.},
year = {2024},
pages = {109217},
}
@article{bernhard_anton_wolf_cluster_2024,
title = {A cluster approach to rationalize shear thinning: {Application} to polymer solutions and suspension fluids},
volume = {68},
doi = {10.1122/8.0000785},
journal = {Journal of Rheology},
author = {Bernhard Anton Wolf},
year = {2024},
pages = {317--325},
}