乙烯基单体乳液接枝改性氯丁胶乳的制备及其机理  

Preparation of Chloroprene Latex Modified with Vinyl Monomers via Emulsion Graft Polymerization and Corresponding Mechanism

作　　者：张凯[1] 沈慧芳[1] 张心亚[1] 蓝仁华[1] 陈焕钦[1] 

机构地区：[1]华南理工大学化学与化工学院,广东广州510640

出　　处：《华南理工大学学报（自然科学版）》2009年第3期19-24,共6页Journal of South China University of Technology(Natural Science Edition)

摘　　要：采用乳液聚合法,使用氧化还原引发剂,将乙烯基单体(甲基丙烯酸甲酯和苯乙烯,即MMA和St)接枝到氯丁胶乳上,研究了乳化体系、引发体系、单体/聚合物质量比及单体组成、反应温度对单体转化率、接枝效率等的影响,并进一步分析了乳液接枝机理.结果表明,MMA和St接枝改性氯丁胶乳的最佳工艺条件为:聚合温度50℃,反应时间5.5 h,引发剂叔丁基过氧化氢-四乙烯五胺占氯丁胶乳干重的0.5%,单体/聚合物质量比为3∶5,MMA与St质量比为3∶2,单体以滴加方式加入,乳化剂十二烷基苯磺酸钠用量占单体总重1.5%.在此条件下,单体转化率可达99.6%,接枝效率为54.9%.红外光谱和凝胶含量分析证明MMA和St接枝到氯丁胶乳主链上.该条件下合成的接枝共聚物乳液配制成的胶粘剂对PVC人造革、SBS橡胶、海绵等具有良好的粘接性能.接枝反应活性点在氯丁胶乳胶粒的表面,接枝过程是一个表面控制过程.Two kinds of vinyl monomers, namely methyl methacrylate （MMA） and styrene （St）, were grafted onto chloroprene latex （CRL） via emulsion polymerization under the action of redox initiator. The effects of the emulsification system, the initiation system, the mass ratio of monomer to polymer, the monomer composition and the reaction temperature on the monomer conversion and the grafting efficiency were then investigated. Moreover, the mechanism of emulsion grafting was analyzed. The results indicate that, in the optimal grafting conditions, that is, a polymerization temperature of 50 ℃, a reaction time of 5.5 h, an initiator （ tea-butyl hydroperoxide/tetraethylenepen- tamine） dosage of O. 5% （based on the dry weight of CRL）, a mass ratio of monomer to polymer of 3： 5, a mass ratio of methyl methacrylate to styrene of 3： 2, and a emulsifier （ sodium dodecylbenzenesulfonate） dosage of 1.5 % （ based on the dry weight of monomers）, the monomer conversion and grafting efficiency of the polymerization with dropwise-added monomers respectively reach 99.6% and 54. 9%. FFIR and gel content analysis confirm that MMA and St are successfully grafted onto the main chain of CRL. The results also show that the adhesive obtained from the graft eopolymer prepared in the optimal conditions is of excellent adhesion properties for PVC leatheroid, SBS rubber and sponge, that the active points of the polymerization locate on the surface of latex particles, and that the grafting process is surface-controlled.

关 键 词：氯丁胶乳 乳液接枝聚合 表面控制 甲基丙烯酸甲酯 苯乙烯 

分 类 号：TQ333.5[化学工程—橡胶工业]