乙烯基硅橡胶为助乳化剂的MMA/BA细乳液共聚合--水溶性引发体系

以十二烷基硫酸钠为乳化剂，乙烯基硅橡胶为助乳化剂、过硫酸铵为引发剂，研究了甲基丙烯酸甲酯和丙烯酸丁酯的细乳液共聚合反应。结果表明，温度、助乳化剂分子量、助乳化剂浓度、乳化剂浓度、引发剂浓度、不同助乳化剂对聚合反应速率和聚合物颗粒大小均有影响，对常规乳液聚合与细乳液聚合的差异进行了比较，并测定了聚合物胶乳的耐盐稳定性。

Miniemulsion Copolymerization of MMA/BA Using Vinyl Silicone Rubber as Cosurfactant--Initiated by a Water-soluble Initiator

Vinyl silicone rubber (VSR) containing unsaturated C=C double bonds was used as co-surfactant in the miniemulsion copolymerization of methyl methacrylate (MMA) and butyl acrylate (BA). In the presence of sodium dodecyl sulfate (SDS) and VSR, miniemulsion of MMA/BA was prepared under ultrasonification, then the miniemulsion copolymerization was carried out with ammonium persulfate as initiator. Effects of variations on the rate of copolymerization were investigated, including reaction temperatures, molecular weights of VSR, types of co-surfactants, concentrations of VSR and SDS. Polymerization rate increased with the increase of reaction temperatures and SDS concentrations. However, with the increase of the molecular weight of VSR, the polymerization rate was lowered. The particle sizes and size distribution of MMA/BA copolymer were not much affected by the VSR concentrations. Under the same conditions, the copolymerization rate of miniemulsion system was compared with that of the conventional emulsion polymerization, the result showed that the former was lower than the latter. The results of salt-tolerance measurement showed that the latexes obtained by VSR co-surfactant was stable in aqueous solution of NaCl with high concentration.