甲基丙烯酸甲酯-苯乙烯共聚物的合成及对铸模性能的影响

采用悬浮聚合法合成了两种不同分子量的甲基丙烯酸甲酯(MMA)-苯乙烯(ST)共聚物．通过凝胶渗逢色谱和元素分析确定产品为无规共聚物，对可发处理后的共聚物的铸模性能进行测定，并研究了单体残留量对共聚物分子量和结构以及分子量对铸模性能的影响，结果表明，(1)随单体残留量增加，PSMMA共聚物的分子量减小，(2)同一种PSMMA共聚物珠粒，单体残留量不同，其结构也不同，(3)PSMMA共聚物的分子量愈大，发泡剂含量愈高，发泡倍率愈大，成型密度愈小，相应的发气量和灼烧后的残留量愈小．

SYNTHESIS OF METHYL METHACRYLATE-STYRENE COPOLYMER AND THE EFFECT ON CASTING MOULDING PROPERTIES

Methyl methacrylate(MMA)-styrene(ST) copolymers were synthesized by a suspension copolymerization with the different molecular weight. Random copolymer is determined by gel permeation chromatograph(GPC) and element analysis. The casting moulding property of PSMMA was determined. The effect of residul monomers on either molecular weight or structure of PSMMA copolymers and the effect of molecular weight on casting moulding property was studies. The results show that: (1) The molecular weight of PSMMA copolymers is reduced with the increase of residul monomers. (2) To the same PSMMA copolymers, their structures are different with the different residul monomers. (3) Both the foaming agent content and foaming times increase with the increase of molecular weight, moulding density, gasification quantity and residuai quantity are reduced with the increase of molecular weight of PSMMA copolymers.