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

The miscibility of blends of bisphenol-A-poly-carbonate (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_xB_yC_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.