Selection of Catalyst for Group Transfer Polymerization of 1-Butadienyloxytrimethylsilane
Selection of Catalyst for Group Transfer Polymerization of 1-Butadienyloxytrimethylsilane
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1-丁二烯氧基三甲基硅烷基团转移聚合催化剂的选择
DOI：
10.1295/polymj.24.669
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发表时间：
1992
期刊：
影响因子：
2.8
通讯作者：
K. Yokota
中科院分区：
文献类型：
--
作者：
H. Sumi;T. Hirabayashi;Y. Inai;K. Yokota
研究了各种路易斯酸在苯甲醛引发的 1-丁二烯氧基三甲基硅烷 (BdTMS) 基团转移聚合 (GTP) 中的催化活性。在研究的路易斯酸中，三种卤化锌（ZnBr2、ZnI2、ZnCl2）和HgBr2 在定量产率下产生了具有窄分子量分布的可溶性聚合物。聚合显然是在不溶性固体催化剂上进行的。其他可溶性路易斯酸催化剂，包括 (C2H5)2AlCl、AlCl3、SnCl4、SnBr4 和 TiBr4，产生的聚合物产率中等至较差，并且通常是胶凝聚合物。通过 1H NMR 监测聚合反应，获得时间与单体和引发剂消耗的曲线，然后根据曲线的斜率估计引发和增长速率。两种速率均按 ZnBr2>ZnI2>ZnCl2 的顺序增强。该顺序与 ZnX2 与苯甲醛以及作为聚合物末端模型的巴豆醛的等摩尔混合物在氯仿-d 中的甲酰基碳的化学位移一致。该顺序也与所得聚合物的 M̅w/M̅n 值的降序一致。因此，使用 ZnBr2 作为催化剂导致 P(BdTMS) 具有最小的 M̅w/M̅n (1.26)，这是通过 GPC 方法测定的。
Catalytic activity of various Lewis acids in the group transfer polymerization (GTP) of 1-butadienyloxytrimethylsilane (BdTMS) initiated with benzaldehyde was investigated. Among the Lewis acids studied, three zinc halides (ZnBr2, ZnI2, ZnCl2) and HgBr2 gave soluble polymers with narrow molecular weight distributions in quantitative yields. The polymerizations proceeded apparently on the insoluble solid catalyst. The other soluble Lewis acid catalysts, including (C2H5)2AlCl, AlCl3, SnCl4, SnBr4, and TiBr4, gave polymers in moderate to poor yields and often gelled polymers. Through 1H NMR monitoring of the polymerization, time vs. monomer and initiator consumption curves were obtained, and then initiation and propagation rates were estimated from slopes of the curves. Both rates were enhanced in an order of ZnBr2>ZnI2>ZnCl2. This order is consistent with that of chemical shifts of formyl carbon of equimolar mixture of ZnX2 with benzaldehyde, as well as crotonaldehyde which is a model for a polymer end, in chloroform-d. This order was also compatible with the decreasing order in M̅w/M̅n values of the resulting polymers. Thus, use of ZnBr2 as the catalyst resulted in P(BdTMS) with the smallest M̅w/M̅n (1.26) which was determined by a GPC method.