复合乳化剂在苯乙烯/甲基丙烯酸甲酯细乳液聚合中的应用

研究了由两种可聚合型乳化剂马来酸酐单十六酯羧酸钠(HEC16)和马来酸酐单甲基丙烯酸羟乙酯羧酸钠(MAEM)组成的复配乳化剂在St/MMA细乳液聚合中的应用。考察了复合乳化剂的比例、浓度对单体转化率和乳胶粒径大小及形貌的影响。研究结果表明,复合乳化剂在细乳液中的cmc较其在水中的cmc大。在复合乳化剂浓度不变的情况下,随MAEM比例的增加,复合乳化剂的cmc逐渐增大,复合乳化剂的转化率在单体聚合的前、后期均逐渐提高,单体液体粒径及乳胶粒径逐渐增大,小粒子逐渐增多,乳胶粒径分布逐渐变宽,单体聚合速率逐渐降低。

APPLICATION OF MIXED SURFACTANTS TO MINIEMULSION COPOLYMERIZATION OF STYRENE/METHYL METHACRYLATE

Mixed surfactants containing MAEM and HEC16 were utilized in the miniemulsion copolymerization of styrene(St)and methyl methacrylate(MMA).The effects of the concentration and mixture ratio of surfactants on the monomer conversions,particle size and latex morphology were investigated.The resuhs showed that the cmc of mixed surfactants in miniemulsion is higher than that of mixed surfactants in water. When the concentrations of the mixed surfactants were constant,with increasing the ratio of MAEM in the mixed surfactants,the conversion of the mixed surfactants increased both at the early stage of monomer conversion and at the 1ate stage of monomer conversion,the sizes of the monomer droplets and latex particle sizes increased correspondingly,more and more small particles appeared,and the polymerization rate of the monomers decreased gradually.