To prepare the high impact polystyrene with good heat resistance

semi-continuous bulk copolymerization of N -phenylmaleimide (PMI) and styrene in the presence of polybutadiene(PB) was carried out in a 2 L stirred tank reactor with a double helical impeller. The effects of polymerization conditions on phase inversion and micro - structure of rubber phase were investigated. It was found that the higher the polymerization temperature and concentrations of PB

initiator and PMI

the earlier the phase inversion occurred

but with raised agitation rate in a later phase inversion. The effects of polymerization technology on the structure of rubber phase

such as particle size

subcontainings in rubber particles

indicate that raising agitation rate

polymerization temperature and the concentration of PB cause higher grafting ratio and larger rubber particles. An increase in the concentration of initiator

BPO

is favorable to raising the grafting ratio. However

an introduction of PMI reduces the value.