复合乳化体系在甲基丙烯酸甲酯/丙烯酸丁酯细乳液共聚合中的应用

用两性离子型乳化剂十二烷基磺基甜菜碱(DSB)和阴离子型乳化剂十二烷基硫酸钠(SDS)复配,作为甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)细乳液共聚体系的复合乳化剂,以十六醇作为助稳定剂,得到了稳定的聚合物理乳液,其乳胶粒径为100~150 nm。考察了复合乳化剂的浓度及配比对单体转化率、所得聚合物相对分子质量、乳胶粒径大小的影响。实验结果表明,在w(DSB)=0.14％的条件下,聚合反应速率和产物最终转化率出现极大值;与纯SDS乳化体系相比,复配乳化体系的聚合反应速率和乳液最终转化率较低;对聚合物胶乳的粒子的均匀程度略有影响;DSB用量增加,产物相对分子质量变大。

APPLICATION OF MIXED SURFACTANTS TO THE MINIEMULSION COPOLYMERIZATION OF METHYL METHACRYLATE/BUTYL ACRYLATEMMA/BA

Mixed emulsifiers containing amphoteric dodecyl sulfobetaine (DSB) and anionic sodium do decyl sulfate (SDS) were utilized in the miniemulsion copolymerization of methyl methacrylate (MMA) and butyl acrylate (BA) with cetyl alcohol as co-stabilizer and stable miniemulsion was obtained. The latex particle size was 100-150 nm. The effects of the concentration and mixture ratio of surfactants on the monomer conversion, molecular weight of copolymer and particle size were investigated. The results showed that the maximum polymerization rate and final conversion appeared at 0. 14% of the DSB; the polymerization rate and the final conversion with mixed emulsifiers were lower than that with SDS alone; the size uniformity of latices was slightly influenced by DSB; and the molecular weight of poly (MMA-co-BA) increased with the added amount of amphoteric emulsifier.