PHASE-BEHAVIOR OF BLENDS OF POLYCARBONATE WITH PARTIALLY MISCIBLE POLYMERS

Phase behavior of blends of bisphenol A polycarbonate (PC) with polystyrene (PS), poly(styrene‐co‐acrylonitrile) (SAN), poly(acrylonitrile‐butadiene‐styrene) (ABS), poly(methyl methacrylate) (PMMA), poly(ethylene terephthalate) (PET), and poly(butylene terephthalate) (PBT) has been investigated. Blends were prepared by screw extrusion and solution casting with weight fractions of PC in the blends varying from 0.90 to 0.10. From the phase diagram of the blends, it appears that PS, SAN, ABS, PMMA, PET, and PBT dissolve more in the PC‐rich phase than does PC in the PS‐, SAN‐, ABS‐, PMMA‐, PET‐, and PBT‐rich phases. Also, from the measured glass transition temperature (Tg) of the screw‐extruded blends and the solution‐cast blends, it appears that compatibility increases more in the PS‐, SAN‐, ABS‐, PMMA, PET‐, and PBT‐rich compositions than in the PC‐rich compositions. Composition‐dependent values of the polymer‐polymer interaction parameters (g12) of various blends were calculated and found to be from 0.034 to 0.053 for equal weights of each of the polymers with PC. Copyright © 1990 John Wiley & Sons, Inc.