K. Schultes, B. A. Wolf, G. Wegner and W. H. Meyer
"Continuous fractionation of poly [(dimethyl)iminodecamethylene-bromide] and molecular weight dependence of glass transition"
Macromolecular Chemistry and Physics 1995, 196, 1005-1016.
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.
preprint number: 158