Subcritical Damped Oscillatory Concentration of Free Radicals in Continuous Mass Polymerization of Alphamethylstyrene Acrylonitrile Methacrylonitrile Terpolymer

摘要

A method of forming polymers containing alphamethylstyrene and acrylonitrile by polymerizing, continuously, under off-azeotrope conditions to improve polyrate without substantially changing the content of alphamethylstyrene in the polymer being formed from that obtained under azeotrope conditions was patented by Schweir and Wu . They obtained polymers of chemically combined alphamethylstyrene (AMS) and acrylonitrile (AN) containing about 70 weight % polymerized AMS possessing significantly higher heat distortion temperature (on the order of 17°C.) than a styrene (S)-acrylonitrile copolymer (SAN) of comparable styrene content. AN provides chemical resistance and toughness in the polymer. AMS/AN copolymers can be blended with impact resistant copolymers of styrene and acrylonitrile grafted on a diene rubber (ABS polymers) to improve the heat resistance of the latter. In this respect, AMS/AN copolymers at about a 70/30 weight ratio are chemically compatible with the ABS polymers and therefore conventionally used in such blends.