Measurement of ternary polymer/solvent equilibrium data by vapor-phase infrared spectroscopy

Vapor–liquid equilibrium (VLE) data for binary toluene/PVAC, methanol/PVAC and ternary toluene/methanol/PVAC systems have been measured at 100 °C by using vapor-phase infrared spectroscopy. Binary data have been compared with literature data measured by different experimental techniques and agreement between our measurements and others was found to be good. The ternary VLE data indicate that the solubility of methanol in PVAC is not influenced by the presence of toluene, while the solubility of toluene is lowered due to presence of methanol. To predict ternary VLE data, the Entropic free volume and Kannan free volume models and the Flory-Huggins theory were used. The predictive abilities of Flory-Huggins theory and the Kannan free volume model are similar and better than that of the Entropic free volume model.