Thermodynamics of the mixture poly(ethylene oxide)/ toluene

Abstract

Excess volumes at 60°C for concentrated mixtures of poly (ethylene oxide) and toluene have been determined.The volume change of mixing is negative, amounting to −0.59% of the total volume at the segment fraction φ2 = 0.5. This result has been used in adjusting the energy parameter X12 = 1.8 cal cm−3, from which theoretical values of the residual chemical potential parameter X, partial molar enthalpies and entropies at different concentrations can be evaluated through the Flory-Prigogine-Patterson theory. Solvent activities for moderately concentrated solutions have been measured by vapour pressure osmometry at 42°and 70°C. Inverse gas chromatography was also used in order to obtain the X value at φ2 = 1. The reduced partial molar excess enthalpy K was calculated from the experimental viscosity-temperature coefficient. Experimental and theoretical values have been compared.