氨基酸希夫碱铜(Ⅱ)催化MMA原子转移自由基聚合的研究

摘要

分别以L-蛋氨酸和L-组氨酸为原料,与水杨醛通过缩合反应合成了两个氨基酸水杨醛希夫碱铜(Ⅱ)配合物(1a和1b).以1为催化剂,2-溴异丁酸乙酯为引发剂,进行甲基丙烯酸甲酯(MMA)的原子转移自由基聚合制得聚甲基丙烯酸甲酯(PMMA),其立构规整度由13C NMR测定.实验结果表明,PMMA数均分子量随MMA转化率线性增长,符合“活性”/可控聚合特征,PMMA分子量分布较窄,主要构象为间同立构.%Two amino acid Schiff base Cu(II) complexes(la and lb) were prepared by condensation of salicylaldehyde with L-methionine and L-histidine, respectively. Methyl methacrylate( MMA) was polymerized using 1 as the catalyst in ethyl 2-bromoisobutyrate initiated atom transfer radical polymerization to obtain poly (methyl methacrylate) (PMMA). The tacticity of PMMA was characterized by 13C NMR. The results showed that the polymerization reaction exhibited the characteristics of active radical polymerization because PMMA molecular weight increases with the increase of MMA conversion , the polydispersity index was narrow, and the predominantly tacticity of PMMA was syndiotac-tic.