APPLICATION OF EQUATION OF STATE THEORIES TO POLY(STYRENE-CO-ACRYLONITRILE)POLY(METHYL METHACRYLATE) BLENDS

The miscibility behavior of poly(styrene-co-acrylonitrile) poly(methyl methacrylate) blends was described by using the equation of state the ory of Flory et al. and the lattice fluid theory. The 'surface area ef fect' inherently included in the latter theory was neglected. For that case it is found that the description of the phase behavior of that t heory is similar then to that obtained by using the theory of Flory et al. Without neglecting this surface area effect, however, it is not p ossible to describe the observed behavior with the lattice fluid theor y. Moreover, for both theories it is necessary to include both, intera ctional and free volume effects, though the observed LSCT behavior is not solely due to free volume effects.