氧化-还原低温引发甲基丙烯酸甲酯/丙烯酸丁酯超浓乳液聚合研究

以乳化剂十二烷基硫酸钠 (SDS)和共乳化剂十六烷醇 (HD)作为复合乳化体系 ,过氧化二苯甲酰(BPO)和N ,N 二甲基苯胺 (DMA)作为氧化还原引发体系 ,甲基丙烯酸甲酯 丙烯酸丁酯 (MMA BA)作为混合单体 ,制备了分散相占 83 %以上的稳定的超浓乳液 ,然后在低温下引发聚合 .探讨了引发剂浓度、氧化剂与还原剂的摩尔比、乳化剂的浓度、液膜增强剂的种类、聚合温度等因素对聚合稳定性和聚合速率的影响 ,测定并计算得到了聚合速率的公式 ;用激光散射粒度分布仪测定了聚合物乳胶粒子的大小及粒径分布 ,用透射电子显微镜观察了聚合物乳胶粒的形态 ,讨论了乳化剂浓度、聚合温度等对乳胶粒形态、大小的影响

STUDY ON CONCENTRATED EMULSION POLYMERIZATION OF METHYL METHACRYLATE/BUTYL ACRYLATE INITIATED BY REDOX SYSTEM

Stable concentrated emulsions of methyl methacrylate/butyl acrylate(MMA/BA) were prepared by using sodium dodecyl sulfate(SDS) and cetyl alcohol(CA) as the compound surfactant,polyvinyl alcohol(PVA) as the major reinforcer of liquid film.The concentrated emulsions polymerization was carried out with benzoyl peroxide/ N,N′ -dimethyl phenylamine (BPO/DMA) as redox initiators at low temperature.When the whole reaction time lasts about 300?min,as is expected,the conversion can be as large as over 96%,and which is higher in comparison with that in concentrated emulsion polymerization initiated by heat initiators.The kinetic behaviors of concentrated emulsion polymerization and time-conversion curves in constant rate range (conversions from 20% to 70%) were investigated.The size and distribution of particle diameter and morphology of latex particles were determined with PCS and TEM.The determination results revealed that concentrations of the compound surfactant and polymerization temperatures etc. affect the shape and size of polymer particles obviously.The experimental results show that with increasing the level of [E],[I] and T, polymerization rate increases.And with increasing the content of [E] and the ratio of [SDS]/[CA],the particle size of polymer latexes and the dispersion index of the particles size decrease; but with increasing the content of [I] and temperature the particle size of the polymer latexes and also the dispersion index of the particles size increase.