Thermodynamic studies of binary and ternary aqueous polymer solutions

The vapor-pressure osmometry (VPO) method was used to measure activities of water for aqueous polymer solutions. The effects of temperature, molecular weight of polymers and their concentrations on the measured activity of water were considered. Using the experimental results, Flory-Huggins interaction parameters for solvent-polymer and polymer-polymer, and the solubility parameters of the used polymers were determined. A simple method was also utilized for determining the Flory-Huggins interaction parameter for solvent in the mixtures of two polymers, polymer(a) and polymer(b). For each case, the mean relative absolute error between calculated and experimental data are reported and it is shown that at studied concentration ranges, the calculated interaction parameter values, for calculating thermodynamic properties, are appropriate.