甲基丙烯酸甲酯的可控/“活性”细乳液光聚合

在室温下, 以2,2,6,6-四甲基-4-羟基哌啶-1-氧自由基(HTEMPO)为调控介质, 1-羟基-环己基-苯基甲酮(Irgacure 184)为引发剂, 采用光化学方法研究了甲基丙烯酸甲酯(MMA)/十二烷基硫酸钠(SDS)/十六醇(CA)/水细乳液体系的光聚合反应控制动力学. 结果表明, 该细乳液体系非常稳定, 在整个聚合过程中即没有絮凝物产生, 也没有沉淀析出, 获得了良好的ln([M0]/[M])与时间、数均分子量与转化率之间的线性动力学关系, 并且在整个聚合反应过程中MMA均聚物的分子量分布比较窄, 其多分散性指数较低(PDI=1.27~1.36), 具有明显的活性聚合特征.

Controlled/Living Photopolymerization of Methyl Methacrylate in Miniemulsion Mediated by HTEMPO

Controlled/living photopolymerization of methyl methacrylate(MMA) in miniemulsion mediated by 4-hydroxy-2,2,6,6-tetramethyl-piperidinyloxy(HTEMPO) was carried out at ambient temperature. MMA miniemulsion was prepared by using anionic surfactant SDS with cetyl alcohol as a costabilizer. The photopolymerization led to stable latices and they were obtained with neither coagulation during synthesis nor destabilization over time. It was found that the obtained MMA homopolymers exhibited relatively narrow molecular weight distributions(PDI=1.27—1.36), which was characterized by GPC. The plots of number-average molecular weight(Mn) vs. conversion and ln([M0]/[M]) vs. time were linear respectively, indicating that the reaction was a controlled/living free radical polymerization.