Thermodynamics of polystyrene solutions. Part 3.—Polystyrene and cyclohexane

Abstract

The excess volumes V^E of mixtures of polystyrene with cyclohexane at 25°C are negative; at a segment fraction of ϕ₂= 0.5, V^E amounts to ca. 0.14 % of the total volume. This result in conjunction with chemical potentials and excess enthalpies determined by Palmen, Schmoll and Jenckel, by Krigbaum and Geymer, and by Scholte are interrelated here by the statistical thermodynamic theory employed in the preceding papers. On assignment of X₁₂= 42 J cm^–3 and Q₁₂= 0.023 J cm^–3 deg^–1 the excess volume V^E, the reduced residual chemical potential χ, and the reduced partial molar excess enthalpy χ_H are well represented at all concentrations. The theory also predicts a lower critical solution temperature in agreement with experiments of Allen et al. and of Tager et al. indicating an LCST in the range 180°C to 210°C for this system.