Miscibility of blends of bisphenol‐A‐polycarbonate and poly(styrene‐co‐acrylonitrile‐co‐hydroxystyrene) terpolymer

Abstract The miscibility of blends of bisphenol‐A‐polycarbonate (BAPC) with the terpolymer poly(hydroxystyrene‐ co ‐acrylonitrile‐ co ‐styrene) (OHS‐AN‐S) and the copolymer poly(hydroxystyrene‐ co ‐acrylonitrile) (OHS‐AN) was investigated. BAPC was found to be miscible with terpolymers incorporating 25–80 mol % hydroxystyrene. The introduction of the acrylonitrile monomer (AN) into poly(styrene‐ co ‐hydroxystyrene) (PSHS) produces a wider “miscibility window” with BAPC compared with that of blends of BAPC with PSHS i.e. a miscible blend is obtained at relatively lower levels of hydroxyl groups in the terpolymer. However, the miscibility range in terpolymer/BAPC blends is affected by the amount of AN monomer incorporated into the terpolymer. This is probably a consequence of the influence of the AN monomer on the closer spatial correlation between the terpolymer and BAPC chains. BAPC is also found to be miscible with the OHS‐AN copolymer within the composition range 12–50 AN mol % in the copolymer. A triangular phase diagram for binary blends of terpolymer/homopolymer (A x B y C z /D) is suggested, to determine the miscible region of the terpolymer compositions in the blends. A model used for predicting the miscibility of binary blends consisting of a homopolymer and a terpolymer was also proposed on the basis of the mean‐field theory, and tested with the experimental results obtained in this work. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007