Samadi, F., Eckelt, J., Wolf, B.A., López-Villanueva, F.J., Frey, H.

"Branched versus linear polyisoprene: Fractionation and phase behavior"

European Polymer Journal 2007, 43, 4236–4243.

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.

preprint number: 284