Investigation of polymer + solvent mixtures by means of cubic equations of state and artificial neural network

In this study, by using four cubic equations of state (EOSs) including van der Waals, Peng-Robinson, Soave-Redlich-Kwong and M4, the specific volume of pure polyethylene, polybutadiene, polyvinylchloride and polyethylenoxid were evaluated. Comparison of the obtained results with experimental data indicated that the obtained results of M4 EOS have higher accuracy. Then, by applying the vdW one-fluid mixing rule for the attractive and repulsive parameters of M4 EOS, the mole fraction of solvent, enthalpy and entropy of mixing for a number of polymer + solvent mixtures at various temperatures were calculated. Then, the evaluated results were compared with corresponding results obtained by Entropic-FV and Zhong group contribution models and the reported experimental data. It was seen that the obtained results by M4 EOS were in closer agreement with the experimental data. Also the phase behavior of polymer + solvent mixtures were studied by using M4 EOS and the lower critical solution temperature (LCST) and upper critical solution temperature (UCST) for these mixtures were predicted and were compared with the available experimental results which indicated acceptable agreement between these results. For obtaining a generalize model to predict the thermodynamic properties of polymer + solvent mixtures, the artificial neural network (ANN) method was used to study the same polymer + solvent mixtures and the mole fraction, enthalpy and entropy of mixing were calculated. The results indicated that the obtained ANN models were more accurate than Entropic-FV, Zhong group contribution models and in also in closer agreement with the results evaluated by M4 EOS.