The effect of chemical composition on the miscibility of styrene/acrylonitrile/fumaronitrile terpolymers with styrene/acrylonitrile copolymers

Blends were prepared of styrene–acrylonitrile–fumaronitrile (SANFN) terpolymers with styrene–acrylonitrile (SAN) copolymers and of SANFN terpolymers with SANFN terpolymers of different compositions. Miscibility was determined by differential scanning calorimetry. For three SANFN terpolymer compositions containing 11–17% fumaronitrile, a range of miscible SAN copolymers was defined. The miscibility can be predicted by using a Flory–Huggins-type mean-field approach.