茂金属/Zn/环氧化合物引发合成含羟基功能团的星形PMMA

采用二茂钛化合物Cp2TiCl2,还原剂(Zn)及引发剂4,4′-亚甲基二(N,N-二缩水甘油基苯胺)(I4)组成的催化体系引发甲基丙烯酸甲酯(MMA)活性/可控自由基聚合,合成了带有羟基功能团的星形无规聚甲基丙烯酸甲酯(PMMA)。探讨了聚合温度,聚合时间及单体与引发剂摩尔比对MMA聚合的影响,实验结果表明,在聚合温度为90℃,MMA]/I4]=200/1时,单体转化率达90%。单体转化率与聚合物分子量之间存在线性增长的关系,表明该聚合属于活性聚合。采用凝胶渗透色谱(GPC),核磁共振(1H-NMR和13C-NMR)等手段表征了聚合物的微观结构和性能,所得PMMA为无规立构、分子量分布较窄(1.41~1.65),且聚合物的臂数与引发剂中环氧功能团的数量一致。

The Synthesis of Star-Shaped Hydroxyl Functionalized Atactic Polymethylmethacrylate Promoted by Metallocene Complex/Zn/Epoxide

Star-shaped hydroxyl functionalized atacticpolymethylmethacrylate was synthesized via living/controlled radical polymerization promoted by titanocene complex in the presence of 4,4′-methylenebis(N,N-diglycidylaniline)(I4) as the initiator,and Zn as the reducing agent.The effect of polymerization conditions such as temperature,time,as well as the ratio of the initiator to monomer on the polymerization performance was investigated.The results indicate that the monomer conversion is up to 90% at 90 ℃ and / =200/1.The number average molecular weight of the polymer linearly depends on the monomer conversion,implying that the performance shows living manner.The structure and properties of the obtained polymer were characterized by gel permeation in chromatography(GPC),nuclear magnetic resonance spectrum(1H-NMR and 13C-NMR).The obtained polymer is atacticspecific and features narrow molecule weight distribution(1.41～1.65) under the typical condition.The number of arms and the functional hydroxyl groups of the polymer molecule are four,good corresponding with the number of the epoxy functional groups of the initiator(I4) used.