On the equation of state of polymer solutions

Abstract

The theory formulated for single and multicomponent systems is applied to polymer solutions. This follows earlier investigations on mixtures of low molecular weight compounds and a binary compatible polymer mixture. The requisite analysis of the polymer constituents, namely polyisobutylene and poly(dimethylsiloxane) shows good agreement between experiment and theory. Similar conclusions apply to the solvents, namely cyclohexane, benzene and hexa(methyl disiloxane). For the solutions, the theory makes predictions at elevated pressures, based on the equation of state of the constituents and low pressure experimentation for the mixtures. Satisfactory results obtain in this manner with deviations increasing with temperature and pressure (maximally 1 kbar). At low pressures, the agreement between experiment and theory is good for all temperatures and compositions.