异戊二烯-甲基丙烯酸甲酯的阴离子嵌段共聚合

摘要

在四氢呋喃（THF）与环己烷的混合溶剂中，以正丁基锂（n-BuLi）为引发剂，采用具有较大空间位阻和特定电荷环境的P配合物为添加剂，实现了异戊二烯（Ip）和甲基丙烯酸甲酯（MMA）的阴离子嵌段共聚。分别采用GPC、^1H—NMR对聚合物的结构进行了分析表征。结果表明：随着THF与环己烷体积比的增大，单体的转化率呈现下降的趋势；同时空间位阻较大的P配合物的加入，堵塞了正、负离子对之间的部分通道，有效地抑制了MMA段聚合副反应的发生，在易于工业化的0℃之下成功合成了分子量分布窄（1．21）的聚异戊二烯一聚甲基丙烯酸甲酯嵌段共聚物（PI—b—PMMA），并且共聚物中PI嵌段以3，4结构链节为主。%Polyisoprene-b-poly(methyl methacrylate)(PI-b-PMMA) was synthesized by anionic polymeri- zation using n-BuLi as the initiator in tetrahydrofuran-cyclohexane mixed solvent. P-complex with large steric hindrance and special electric charge environment was used as an additive in the system. The molecu- lar structure of prepared block copolymers was characterized by GPC and 1H-NMR. Results showed that the conversion decreased with the increasing of the volume ratio of tetrahydrofuran-cyclohexane. P-com- plex could inhibit the side reactions of MMA effectively, which can partially block the channels between positive and negative ions. Due to the introduction of P-complex, PI-b-PMMA with narrow molecular weight distribution(1.21) was synthesized successfully at 0℃ and easy to be industrialized. The PI chains in the copolymer were mainly composed of 3,4-structure.