四官能度过氧化物引发制备高抗冲聚苯乙烯

摘要

The synthesis of high impact polystyrene (HIPS) with the usage of a tetrafunctional peroxide initiator was investigated. The polymerization performance of a commercial initiator polyether poly-￡-butylperoxy carbonate (JWEB50) was compared with that of its monofunctional counterpart, tert-butyl (2-ethylhexyl)monoperoxycarbonate (TBEC). It was shown that the polymerization kinetic curves completely overlapped at the same polymerization temperature when the molar concentrations of [O-O] were equal for these two initiators. And the higher the molecular weights, the equal polymerization rate could be obtained simultaneously by tetrafuctional JWEB50 compared to monofuctional TBEC under the same other conditions. The effect of polymerization temperature on molecular weight of HIPS prepared with JWEB50 or TBEC was investigated. It suggested that the molecular weight changed slower with the increase of polymerization temperature for JWEB50, compared to TBEC. That meant the molecular weight-increasing effect of JWBE50 would be more pronounced at high polymerization temperatures. The effect of initiator type on graft efficiency was also studied. At the same molar concentration of initiator, it was found that the graft efficiency was dramatically improved with the usage of JWEB50. It was also shown that the graft efficiency increased with the increase of polymerization temperature, but decreased with the increase of conversion. And the evolutions of viscosity during the preparation of HIPS recorded on-line by rotation rheometer (HAAKE RS6000) were very similar for these two initiators when the molar concentrations of [O-O] were equal. The two viscosity versus time curves completely overlapped with each other. And the phase inversion turned out to be flat in the curves. The phase inversion flats for both initiators were found to occur at a monomer conversion range around 18%-25%.%高抗冲聚苯乙烯(HIPS)可通过顺丁橡胶(PB)接枝苯乙烯共聚制备,相比通用聚苯乙烯(GPPS),其抗冲性能高、拉伸形变大,但这些性能受HIPS分子量及分布、接枝效率、橡胶粒子形态及大小的影响很大[1].制备时可改变剪切速率、橡胶类型及用量、引发剂用量来调节产物分子量及分布、接枝效率、橡胶粒子形态及大小,进而控制HIPS的性能[2].