氯乙烯/邻苯二甲酸二烯丙基酯悬浮共聚特征

对４５℃时的氯乙烯／邻苯二甲酸二烯丙基酯（ＶＣ／ＤＡＰ）的悬浮共聚进行了研究，得到表观竞聚率ｒＶＣ＝０７６９、ｒＤＡＰ＝０３７４．凝胶点对应的ＤＡＰ临界起始浓度在０４６６～０４９３ｍｍｏｌ／ｍｏｌＶＣ之间（聚合转化率为８０～８５％），当ＤＡＰ起始浓度小于临界浓度时，ＶＣ／ＤＡＰ共聚物均为溶胶，溶胶平均聚合度随ＤＡＰ起始浓度和聚合转化率的提高而增大；当ＤＡＰ起始浓度大于临界浓度时，共聚物由溶胶和凝胶组成，凝胶含量随ＤＡＰ浓度和聚合转化率的提高而增加，溶胶聚合度则随ＤＡＰ浓度的提高而减小．在凝胶点前，共聚物的分子量分布随ＤＡＰ浓度的增加而变宽；凝胶点以后，分子量分布随ＤＡＰ浓度的增加而变窄．

THE FEATURES OF VINYL CHLORIDE/DIALLYL PHTHALATE SUSPENSION COPOLYMERIZATION

Vinyl chloride/diallyl phthalate(VC/DAP) suspension copolymerizations were carried out in a 5L autoclave and 200ml stainless steel reactors at temperature of 45℃.The apparent reactivity ratios of VC and DAP were calculated as r VC =0 769, r DAP =0 374.The existence of the gel point of the VC/DAP copolymerization system was ascertained and the critical initial concentration of DAP ( f cr ) at which gel began to form was in range of 0 466～0 493mmol/mol VC.The degree of polymerization ( DP ) and indexs of distribution of molecular weight ( MWD ) of copolymer increased as the initial concentration of DAP ( f 20 ) increased when f 20 was less than f cr , and DP also increased with increase of conversion.When f 20 was larger than f cr ,DP and indexs of MWD of sol fraction decreased as f 20 increased,but the gel content increased,the gel content also increased as conversion increased.