Miscibility mapping in some blends involving poly(styrene‐co‐acrylonitrile)

Binary interaction parameters, Xij have been determined for the monomer pairs, styrene‐acrylonitrile and methyl methacrylate‐acrylonitrile from phase separation measurements in homopolymer‐copolymer blends. These have been used to predict regions of miscibility in different blends of statistical copolymers where the components were (a) poly(styrene‐co‐acrylonitrile), (b) poly(styrene‐co‐methylmethacrylate) and (c) poly(methylmethacrylate‐co‐acrylonitrile). Agreement between prediction and experiment was good in all cases. Extensive miscibility ranges were obtained for blends of (a) with (b), and (a) with (c), but combinations of (b) with (c) are immiscible.