Upper and Lower Critical Solution Temperatures in the Cosolvent System Acetone(l) + Diethyl Ether(2) +Polystyrene(3)

Abstract

Phase diagrams for different molecular weight fractions of polystyrene in the mixed solvent system acetone+diethyl ether have been obtained. The system shows a variation of upper and lower critical solution temperatures with solvent composition which indicates the cosolvent nature of the mixed solvent. No solvent composition is found which can dissolve high molecular weight poly styrene (M> 106). The separation of critical solution temperatures can be predicted by the Prigogine theory of polymer solution thermodynamics, but not the absolute values.