PREDICTION AND MANIPULATION OF THE PHASE MORPHOLOGIES OF MULTIPHASE POLYMER BLENDS .2. QUATERNARY SYSTEMS

We have applied our model concerning the phase structures of multiphas e polymer blends to quaternary blends of polyethylene, polypropylene, polystyrene and poly(methyl methacrylate) of different overall composi tions. Predictions of the phase morphologies of such multicomponent bl ends are based on minimization of the total interfacial free energy of the system. We compare predictions of the model with experimental obs ervations, and show agreement in every case between the predicted and experimental morphologies. Furthermore, we show that the phase structu re of a quaternary blend can be converted from one type of phase morph ology to another, e.g. from an encapsulation type to the dispersion ty pe, by using an interfacially active block copolymer. This shows the p ossibility of adjusting the phase morphologies of multicomponent syste ms as desired. (C) 1997 Elsevier Science Ltd.