Quantitative synthesis of star-shaped poly(vinyl ether)s with a narrow molecular weight distribution by living cationic polymerization.
Quantitative synthesis of star-shaped poly(vinyl ether)s with a narrow molecular weight distribution by living cationic polymerization.
复制标题
DOI：
10.1021/ja057611h
复制
发表时间：
2006-05
影响因子：
15
通讯作者：
T. Shibata;S. Kanaoka;S. Aoshima
中科院分区：
文献类型：
--
作者：
T. Shibata;S. Kanaoka;S. Aoshima
具有窄分子量分布的星形聚乙烯基醚是通过基于活性阳离子聚合的活性聚合物与二乙烯基化合物的聚合物连接反应获得的。例如，异丁基乙烯基醚（IBVE）的活性聚合物（DP（n）= 50-300），用阳离子原/EtAlCl（2）在0℃下在己烷中，在乙酸乙酯存在下制备，与少量1,4-环己烷二甲醇二乙烯基醚（DVE-1）反应，以定量产率（100％）得到星形聚（IBVE）。此外，这种星形聚合物的一个显着特点是分子量分布极窄（M(w)/M(n) = 1.1-1.2）。二乙烯基化合物的结构和连接反应的反应条件是实现星形聚合物定量产率的关键因素。据我们所知，这是通过一锅聚合物连接反应选择性制备窄分子量分布星形聚合物的第一个例子，这是任何其他机制从未实现过的。每个分子的 M(w) 和臂数范围分别为 6 x 10(4) 至 30 x 10(4) 和 9 至 44。还定量合成了热敏星形聚合物，并且发现产物经历了敏感的相分离和物理凝胶化。
Star-shaped poly(vinyl ether)s with narrow molecular weight distributions were obtained from polymer-linking reactions of living polymers with a divinyl compound based on living cationic polymerization. For example, living polymers (DP(n) = 50-300) of isobutyl vinyl ether (IBVE), prepared with a cationogen/EtAlCl(2) at 0 degrees C in hexane in the presence of ethyl acetate, were allowed to react with a small amount of 1,4-cyclohexanedimethanol divinyl ether (DVE-1) to give a star-shaped poly(IBVE) in quantitative yield (100%). In addition, a notable feature of this star-shaped polymer was extremely narrow molecular weight distribution (M(w)/M(n) = 1.1-1.2). The structure of divinyl compounds and reaction conditions for the linking reaction are key factors for achieving quantitative yield of star-shaped polymers. To our best knowledge, this is the first example of selective preparation of star-shaped polymers with narrow molecular weight distribution via one-pot polymer-linking reactions, which has never been achieved in any other mechanisms. The M(w) and the number of arms per molecule ranged from 6 x 10(4) to 30 x 10(4) and 9 to 44, respectively. Thermosensitive star polymers were also synthesized in quantitative yield, and the products were found to undergo sensitive phase separation and physical gelation.