Anionic polymerization of alkyl methacrylates in the presence of diethylzinc
Anionic polymerization of alkyl methacrylates in the presence of diethylzinc
复制标题
二乙基锌存在下甲基丙烯酸烷基酯的阴离子聚合
DOI：
10.1002/macp.1995.021960702
复制
发表时间：
1995
影响因子：
2.5
通讯作者：
S. Nakahama
中科院分区：
文献类型：
--
作者：
H. Ozaki;A. Hirao;S. Nakahama
研究了甲基丙烯酸甲酯（MMA）、甲基丙烯酸异丙酯（IPMA）和甲基丙烯酸叔丁酯（TBMA）在二乙基锌存在下的四氢呋喃中的阴离子聚合。在反应混合物中加入二乙基锌显著降低了用二苯基甲烷化钾引发的甲基丙烯酸酯的聚合速率，得到具有预测分子量和非常窄的分子量分布的聚合物，而在不存在二乙基锌的情况下用二苯基甲烷化钾生产的PMMA和聚（IPMA）具有相当宽的分子量分布。PMMA、聚（IPMA）和聚（TBMA）的立体定向性不受二乙基锌的影响。由MMA与TBMA的嵌段共聚反应结果发现，二乙基锌的加入可显著提高PMMA阴离子增长端的稳定性。二乙基锌对链增长端基上烯醇阴离子的弱配位作用可能是二乙基锌对链增长端基上烯醇阴离子的弱配位作用所导致的。
The anionic polymerizations of methyl methacrylate (MMA), isopropyl methacrylate (IPMA), and tert-butyl methacrylate (TBMA) in THF in the presence of diethylzinc were investigated. The addition of diethylzinc to the reaction mixture remarkably lowers the polymerization rates of the methacrylates initiated with potassium diphenylmethanide to afford polymers with the predicted molecular weights and very narrow molecular weight distributions, while PMMA and poly(IPMA) produced with potassium diphenylmethanide in the absence of diethylzinc have rather broad molecular weight distributions. The stereospecificities of PMMA, poly(IPMA) and poly(TBMA) are not affected by diethylzinc. From the result of the block copolymerization of MMA with TBMA, it was found that the presistency of the anionic propagating end of PMMA is significantly enhanced by the addition of diethylzinc. The retardation of the polymerization rates and the enhancement of the persistency of the propagating end in the presence of diethylzinc may be caused by the weak coordination of diethylzinc toward the enolate anions at the propagating end groups.