甲基丙烯酸甲酯/丙烯酸/水反相无皂微乳液体系的聚合

Polymerization of methyl methacrylate/acrylic acid/water soap-free inverse microemulsions

采用滴定法描绘了甲基丙烯酸甲酯(MMA)/丙烯酸(AA)/H2O无皂微乳液体系的三元相图,用电导率法对单相微乳液区域进行了类型划分.在相图研究的基础上,考察了引发剂(AIBN)用量、体系AA含量和水含量对MMA/AA/H2O反相无皂微乳液体系聚合速率的影响.结果表明,聚合速率随引发剂用量和AA含量的增加逐步加快,随体系水含量的提高出现极大值.得到动力学关系,表明AA的乳化促进作用显著,聚合在连续相进行的同时亦在分散相液滴内进行.此外,环境扫描电镜的测试结果表明,所得聚合产物具有明显的孔穴结构.

The ternary phase diagram of methyl methacrylate （MMA）/acrylic acid （AA）/water soap-free microemulsion system was figured out by the conventional titration technique, and the domains of different types of single phase microemulsions were partitioned with conductivity measurement. Based on the phase diagram, the influence of the amount of initiator （AIBN）, the contents of AA and water on the rate of polymerization in MMA/AA/H20 soap-free inverse microemulsions was investigated. The results showed that polymerization rate increased with increasing amount of initiator or increasing content of AA and there appeared a peak value of rate with increasing content of water. The kinetic relation was obtained, which indicated that AA was an effective emulsifier to enforce and hasten polymerization in dispersed droplets at the same time with conventional polymerization in the continuous phase. In addition, the morphology of the products from soap-free microemulsion was observed under an environment scanning electron microscope and the existence of microporous structure was found.