可聚合表面活性剂在RAFT乳液聚合中的作用机理

Mechanism of the Polymerizable Surfactant in RAFT Emulsion Polymerization

以可聚合表面活性剂甲基丙烯酰氧乙基十二烷基二甲基溴化铵(C12N+)为乳化剂,羧端基十二烷基三硫代酯(DMP)为可逆加成-断裂链转移(RAFT)试剂,苯乙烯为单体,在不使用助稳剂条件下采用RAFT乳液聚合成功制备了聚苯乙烯纳米颗粒并对聚合机理及反应条件进行了初步研究。结果表明,C12N+乳化剂能在反应过程中参与单体共聚,形成的预聚物能起到助稳剂作用,反应温度以70℃为宜,产物平均粒径约为36nm,分子量分布小于1.5。

In this paper, a cationic polymerizable surfactant （methaeryloxyethyl dodecydimethyl ammonium bromide, C12N^＋） was used to replace conventional emulsifiers in reversible addition fragmentation chain transfer （RAFT） emulsion polymerization of styrene. 2 dodecylsulfanylthiocarbonyl-sulfanyl-2-methyl propionic acid（DMP） was used as a RAFT agent. Polymerization mechanism and reaction conditions had been studied. The results indicate that C12N^＋ can play the roles of an emulsifier and a costabilizer at the same time. The prepolymer of C12N^＋ can inhibit the migration of styrene in the polymerization process. Nanoscale latex particles with average diameter 36 nm were prepared at 70~. The molecule weight of P（St-C12N^＋ ） is well controlled and the molecular weight distribution is less than 1.5.