The phase behavior and mechanical properties of polyarylate and polycarbonate blends

Abstract

AbstractThe phase behavior and mechanical properties of a series of polyarylate/polycarbonate blends were studied. The polymers are known to transesterify, the extent of which depends upon the thermal and shear history and affects phase behavior and properties. Single screw extrusion, twin screw extrusion, and solution casting were employed for blend preparation. Two transition temperatures, corresponding to a polycarbonate‐rich phase and to a polyarylate‐rich phase, were seen in blends that were solution cast or compounded in a single screw extruder at 285°C. But after injection molding a single Tg was observed, When annealed at 180°C for several hours the molded blend was found to phase separate. Blends that were compounded in a twin screw extruder exhibited a single Tg and could not be phase separated. The flexural and tensile properties of blends that were prepared in a twin screw extruder show a small positive synergism. But the impact properties were substantially below the rule of mixtures values, probably the result of advanced exchange reaction and thermal degradation.