Predicting polymer-polymer miscibility with a group contribution metho

Application of a group contribution method, which uses interaction parameters determined from heats of mixing of liquids, to predict heats of mixing and miscibility between polymer mixtures is demonstrated. Two group contribution methods, the UNIQUAC/UNIFAC method developed by Abrams & Prausnitz and Fredenslund, Jones, & Prausnitz in 1975, and the Modified Guggenheim Quasichemical (MGQ) method, developed by this work, are evaluated in depth. The MGQ method was found to fit heats of mixing of polar liquid compounds to within about 10 $sim$ 15%, while the UNIQAC/UNIFAC method is less accurate by a factor of about two.;The group interaction parameters determined by the MGQ method are demonstrated to predict the binary interaction densities and state of miscibility of poly(vinyl chloride)/aliphatic polyester blends, poly(vinyl chloride)/polymethacrylate blends, a blend containing polycarbonate with poly(methyl methacrylate), and a blend containing poly(methyl methacrylate) with poly(ethylene oxide). Comparisons between these predictions and experimental observations, reported in the literature, are quite favorable.;The binary interaction densities and miscibility of blends containing polyesters with the polyhydroxyl ether of bisphenol-A, Phenoxy, were found to strongly depend on the temperature at which prediction is performed, or on the way nonrandomness of mixing is considered. With proper choice of temperature or proper suppression of the estimated nonrandom effects, the observed interactions between these polymers can still be satisfactorily estimated by the model.;Appreciable discrepancies are found between the predicted and the observed miscibility between poly(epichlorohydrin)/aliphatic polyester blends, and between poly(styrene-co-acrylonitrile) based blends. A study of heats of mixing of polystyrene oligomers with several other compounds shows that differences between polystyrene and its liquid analog is the major factor responsible for the discrepancies between predictions and observations in these systems. The source of the discrepancies between the predicted and the observed miscibility between poly(epichlorohydrin)/aliphatic polyester blends needs further study.