Solubility of Acetone-Methanol Mixtures in Matrimid Glassy Polymer: Experimental Data and Modelling through NET-GP and PC-SAFT

In this work, the PC-SAFT equation of state and the NET-GP approach have been considered for the description of the thermodynamic equilibrium between liquid acetone-methanol mixture and Matrimid glassy polymer. Pure component parameters of the PC-SAFT EoS for the system under consideration were retrieved from literature and checked by predicting the vapor pressure and saturated molar volumes of both Methanol and Acetone. Considering the binary mixture, isothermal VLE data at 35°C were fitted by using PC-SAFT, in order to derive binary interaction coefficients, the latter then proved to be able to correctly describe also the volume of the liquid mixture at 35°C and 1 bar. Considering the binary Acetone-Matrimid and Methanol-Matrimid systems, binary interaction and swelling coefficients needed for the description of the glassy phase were retrieved by fitting pure component vapor sorption isotherms at 35°C through the NET-GP approach coupled with PC-SAFT equation of state. Finally, based on the parameters obtained from the binary mixtures, the ternary Acetone-Methanol-Matrimid system at 35°C and 1 bar was predicted, without using additional parameters. The results were compared with experimental data related to liquid sorption in the polymer as obtained by coupling FTIR-ATR analysis and gravimetric methods. The agreement was remarkable testifying to the ability of the proposed approach to describe sorption of binary mixtures involving hydrogen bonding compounds in glassy polymers.