An excess Gibbs energy model to study the phase behavior of aqueous two-phase systems of polyethylene glycol plus dextran

摘要

A new model for the excess Gibbs energy named UNIQUAC-NRF is presented to study the phase behavior of aqueous two-phase polymer-polymer systems. The assumptions of the NRTL-NRF model and the local composition expression of the UNIQUAC model have been used in the development of the new model. Using the random state as a reference state, a model for g(E) as function of the nonrandom factor has been developed for binary and multicomponent mixtures. The new model was applied for the prediction of the phase behavior of aqueous two-phase polymer-polymer systems of polyethylene glycol + dextran. The interaction parameters were obtained for 25 systems. Comparing the results of the UINQUAC and UNIQUAC-NRF models, it was shown that the present model is more accurate. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 34]