Wolf, B. A., Kuleznev, V.N., Pozharnova, N.A.

"Critical phenomena in solutions of the polystyrene-polyacrylonitrile random copolymer and its blends with polystyrene "

Polymer Sciences Series A 2002, 7, 44, 767-772.

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.

preprint number: 238