MMA-BA-DMAEMA乳液共聚合体系的稳定性

Stability of emulsion copolymerization system of MMA BA DMAEMA

采用间歇及半连续乳液聚合方式，合成得到了甲基丙烯酸甲酯－丙烯酸丁酯－甲基丙烯酸二甲氨基乙酯三元共聚物胶乳．系统研究了乳化剂种类和浓度、聚合温度、官能单体含量和乳化单体进料方式及进料速率对聚合体系稳定性的影响．试验结果表明，对含有氨基官能单体的共聚合体系，合适的乳化剂体系只能通过聚合稳定性试验确定，单体乳化稳定性试验并不能提供有价值的信息．试验结果还表明，官能单体甲基丙烯酸二甲氨基乙酯的含量对聚合体系稳定性没有明显的影响，乳化剂用量增加、聚合温度降低、乳化单体进料速率减慢均有利于聚合体系的稳定．半连续乳液聚合比间歇乳液聚合更易得到稳定乳液，而种子和无种子半连续聚合过程的稳定性相似．

The terpolymer latex of MMA BA DMAEMA was prepared in both batch and semicontinuous emulsion copolymerizations.The effects of emulsifier type and concentration,polymerization temperature,the feed policy and feed rate of emulsified monomer on the stability of polymerization system were studied systematically.The results show that the HLB is not a critical value for selecting the emulsifier used in the emulsion polymerization containing DMAEMA.The available method for determining emulsifier system is still directly by the stability observation in the polymerization runs.The emulsifier type is a key factor influencing the stability of polymerization system.The results also show thattan increase of the emulsifier concentration and a decrease of polymerization temperature will improve the stability of polymerization system.The content of functional monomer DMAEMA does not affect the stability of polymerization system obviously.A reduction of the feed rate of the emulsified monomers is favorable to the stability of polymerization system.The stability of batch polymerization is inferior to that of semi continuous polymerization for this system,but the seeded and unseeded semi continuous emulsion polymerization processes are similar in polymerization stability.