Vapor-Liquid (VLE) and Liquid-Liquid (LLE) Phase Equilibria Calculations for Polystyrene + Methylcyclohexane and Polystyrene + Cyclohexane Solutions

This paper presents the vapor-liquid (VLE) and liquid-liquid (LLE) phase equilibria predictions for polystyrene in two theta solvents: cyclohexane andmethylcyclohexane.VLE calculations were performed with the Elbro free volume method and a modified version of the PC-SAFT method, as well as with three UNIFAC type group contribution models: Entropic Free Volume + UNIFAC VLE 1coeff., Entropic Free Volume + UNIFAC VLE 2coeff., and Oishi-Prausnitz + UNIFAC VLE 2coeff. Solvent activities were calculated for the polystyrene + cyclohexane and polystyrene + methylcyclohexane solutions, and compared with experimental data. LLE predictions were performed with PC-SAFT method and compared with experimental data. The obtained results show that the PC-SAFTmethod gave themost accurate predictions for bothVLE as well as LLE for the systems studied.