聚氯乙烯中烯丙基氯含量的研究

用电位滴定法测定了聚氯乙烯(PVC) 中的烯丙基氯含量, 研究了烯丙基氯含量与PVC 相对分子质量的关系; 用氯仿萃取了PVC 中不同相对分子质量的级分, 测定了二个级分的烯丙基氯含量。结果发现聚合物中较低相对分子质量部分的炳丙基氯含量比较高相对分子质量部分的高。表明在聚合反应中控制相对分子质量分布是很重要的, 为了提高PVC 的热稳定性, 在氯乙烯聚合反应中要减少低相对分子质量部分的PVC 的生成。

Study on chloroallyl group content in PVC

In this paper, the chloroallyl group content of PVC have been determined by potentiometric titration and the correlation between chloroallyl group content and molecular weight has been studied. Fractions of PVC of different molecular weight have been isolated from the polymer by extraction fractionatin using chloroform. The chloroallyl group content has been determined for the two fractions solved in chloroform. It is found that the content of chloroallyl groups for the lower molecular weight extracts is larger than that for the higher molecular weight extracts. The results show that the controlled distribution of molecular weight of PVC is of prime importance in the polymerization reaction. Further, in the polymerization reaction of vinyl chloride, the lower molecular weight fraction should be decreased in order to increase thermal stablity of PVC.