1996 Volume 29 Issue 2 Pages 217-222
A gas chromatographic method was used in order to measure vapor-liquid equilibria for solvent (1)-polymer (2) systems in which the polymers were polystyrene, poly(a-methyl) styrene and the solvents were benzene, toluene, cyclohexane, methylisobutylketone, ethylacetate, and vinylacetate. The activity coefficients of solvents for solvent (1)-polymer (2) systems were measured at infinite dilution and the modified ASOG (Analytical Solution of Group) model was suggested to describe vapor-liquid equilibria of those systems within a range of temperatures 423.15 K through 498.15 K. The model consists of the original ASOG and the free volume term. An external degree of freedom in the free volume term empirically became to a C1 = α + β/T as a function of temperature. Each term in the modified ASOG model is based on the weight fraction. The external degree of freedom in the model was estimated by experimental data within a range of temperatures. As a result of doing it, the infinite dilution activity coefficients calculated were agreed with the experimental data within an error of 0.1%.
