HEAT-RESISTANT STYRENE ALPHA-METHYLSTYRENE COPOLYMERS MADE VIA CONTINUOUS ANIONIC-POLYMERIZATION AT HIGH-TEMPERATURE

Styrene/α‐methylstyrene (SAMS) copolymers were produced containing up to 67 weight % AMS. The polymerizations were carried out using anionic polymerization at high temperature (100°C) in a CSTR type reactor. The reactivity ratios for the anionic copolymerization of styrene (M1) and AMS (M2) were estimated to be r1 = 60 and r2 = 0.01. Thermal degradation of a SAMS copolymer containing 50 weight % AMS was studied and compared with free radical polystyrene (FRPS) and anionic polystyrene (APS). The relative rate of styrene monomer generation for the three polymers followed the order SAMS > FRPS > APS. The relative rate of loss of molecular weight for the three polymers was FRPS > APS > SAMS. This indicates that the main mechanism of thermal degradation of SAMS copolymers is depolymerization rather than chain scission. Copyright © 1990 John Wiley & Sons, Inc.