MELT BLENDS OF SAN WITH ACRYLONITRILE-STYRENE-ACRYLIC ESTER COPOLYMER

Melt blends of SAN with acrylonitrile-styrene-acrylic ester copolymer (ASA) were prepared using a twin-screw extruder. Morphology, mechanica l and viscoelastic properties of the SAN/ASA blend were studied in the full range of compositions. TEM micrographs showed a bimodal distribu tion of the rubber particles with 0.7 mu m and 0.2 mu m in diameter. T he transition from brittte to ductile mode of failure occurred in the range of 20-30 wt% ASA. The blends showed typical behavior of an immis cible system where melt viscosity exhibited a positive deviation from the log additivity. The glass transition temperature (Tg) of blends di d not shift with increasing ASA content, indicative of complete phase separation.