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During the last years, the GC-Flory EOS has been used to calculate activity coefficients in polymer-solvent mixture [1,2,3]3. The GC-Flory EOS using parameters based on vapor-liquid equilibrium (VLE) was also applied to the prediction of the miscibility/immiscibility phenomena of monodisperse polymer-solvent systems [4], but it was shown that the model was capable to predict only qualitatively the phase diagrams typical of LLE of polymer solutions. In principle, LLE compositions may be calculated using any model for Gibbs energy, but models relying on a group contribution approach, such as the UNIFAC model, but they require a special set of parameters [5]. In this work, the model parameters have been estimated from the experimental LLE data. The prediction of LLE phase behavior of polymer solutions with the new LLE parameter tables is significantly improved over the ones obtained using the VLE parameter tables. The comparison of the accuracy of the prediction was carried out, and it was shown that the model was capable quantitatively to predict the most relevant types of phase diagrams typical of LLE of polymer solutions (i.e. phase diagrams of the UCST, LCST, combined UCST and LCST, and "hourglass" types). _________________________________ [1] F.Chen, Aa.Fredenslund, P.Rasmussen, Ind.Eng.Chem.Res., 29, 875 (1990). [2] G.Bogdanić, Aa.Fredenslund, Ind.Eng.Chem.Res., 33, 1331 (1994). [3] G.Bogdanić, Aa.Fredenslund, Ind.Eng.Chem.Res., 34, 324 (1995). [4] A.Saraiva, G.Bogdanić, Aa.Fredenslund, Ind.Eng.Chem.Res., 34, 1835 (1995). [5] T.Magnussen, P.Rasmussen, Aa.Fredenslund, Ind.Eng.Chem.,Proc.Des.Dev., 20, 331 (1981). |
