Living cationic polymerization of vinyl ethers with a urethane group
Living cationic polymerization of vinyl ethers with a urethane group
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乙烯基醚与氨基甲酸酯基团的活性阳离子聚合
DOI：
10.1002/pola.20145
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
T. Kodaira
中科院分区：
文献类型：
--
作者：
Takeshi Namikoshi;T. Hashimoto;T. Kodaira
为了研究含氨基甲酸酯基团的乙烯基醚的活性阳离子聚合的可能性，在二氯甲烷溶剂中，在-30 °C下，用氯化氢/氯化锌引发体系（[单体] 0 = 0.30 M，[HCl] 0 /[ZnCl 2 ] 0 = 5.0/2.0 mM）聚合正丁基氨基甲酸4-乙烯氧基丁酯（1）和苯基氨基甲酸4-乙烯氧基丁酯（2）。1的聚合是非常缓慢的，并得到只有低分子量的聚合物的数均分子量（Mn）约为2000，即使在100%的单体转化率。产物的结构分析表明，由于单体1的氨基甲酸酯基团，发生了链转移反应。相比之下，乙烯基醚2的聚合进行得比1快得多，并导致定量产率的具有窄分子量分布（MWD ≤ 1.2）的高分子量聚合物。产物聚合物的Mn与单体转化率成正比地增加，并且在向几乎完全聚合的反应混合物中顺序加入新鲜单体进料后继续线性增加，而聚合物的MWD保持窄。这些结果表明由乙烯基醚2形成活性聚合物。单体1和2之间活性性质的差异可归因于单体的氨基甲酸酯取代基的吸电子能力的差异，即1的正丁基与2的苯基。
To study the possibility of living cationic polymerization of vinyl ethers with a urethane group, 4-vinyloxybutyl n-butylcarbamate (1) and 4-vinyloxybutyl phenylcarbamate (2) were polymerized with the hydrogen chloride/zinc chloride initiating system in methylene chloride solvent at -30 °C ([monomer] o = 0.30 M, [HCl] 0 /[ZnCl 2 ] 0 = 5.0/2.0 mM). The polymerization of 1 was very slow and gave only low-molecular-weight polymers with a number-average molecular weight (M n ) of about 2000 even at 100% monomer conversion. The structural analysis of the products showed occurrence of chain-transfer reactions because of the urethane group of monomer 1. In contrast, the polymerization of vinyl ether 2 proceeded much faster than 1 and led to high-molecular-weight polymers with narrow molecular weight distributions (MWDs ≤ ∼1.2) in quantitative yield. The M n 's of the product polymers increased in direct proportion to monomer conversion and continued to increase linearly after sequential addition of a fresh monomer feed to the almost completely polymerized reaction mixture, whereas the MWDs of the polymers remained narrow. These results indicated the formation of living polymer from vinyl ether 2. The difference of living nature between monomers 1 and 2 was attributable to the difference of the electron-withdrawing power of the carbamate substituents, namely, n-butyl for 1 versus phenyl for 2, of the monomers.
影响因子：
5.5
作者：
M. Kamigaito;M. Sawamoto;T. Higashimura
通讯作者：
M. Kamigaito;M. Sawamoto;T. Higashimura