Di‐isotacticity of poly(methyl propenyl ether) and double‐bond opening of methyl propenyl ether in cationic polymerization
Di‐isotacticity of poly(methyl propenyl ether) and double‐bond opening of methyl propenyl ether in cationic polymerization
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聚甲基丙烯醚的双全同立构规整度和阳离子聚合中甲基丙烯醚的双键开环
DOI：
10.1002/pol.1967.150051204
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发表时间：
1967
期刊：
影响因子：
--
通讯作者：
T. Kuroda
中科院分区：
文献类型：
--
作者：
Y. Ohsumi;T. Higashimura;S. Okamura;R. Chǔjǒ;T. Kuroda
本文用核磁共振谱研究了阳离子聚合所得聚甲基丙烯基醚的双等规度。将聚合物的β-甲基质子的NMR谱与β-次甲基质子谱解耦以确定聚合物中的双全同立构分数。β-甲基质子在8.78和8.89 τ处的信号分别根据苏式和赤式二全同二单元的光谱进行估计。在BF_3·O（C_2H_5）_2催化下，反式单体得到了苏式双等规的结晶聚合物。另外，顺式单体产生无定形聚合物，并且它是苏式和赤式双全同立构结构的混合物。从这些结果中，可以得出结论，在反式单体中的双键打开完全在顺式类型，在顺式单体顺式和反式开口发生在几乎相同的速率。
The di-isotacticity of poly(methylpropenyl ether) obtained by the cationic polymerization has been studied by NMR spectra. The NMR spectra of β-methyl protons of the polymer are decoupled from the β-methine proton spectra to determine the di-isotactic fraction in a polymer. The signals of β-methyl protons at 8.78 and 8.89 τ are estimated as spectra based on threo- and erythro-di-isotactic diads, respectively. With BF3·O(C2H5)2 as a catalyst, the trans monomer yields a crystalline polymer and its structure is threo-di-isotactic. Otherwise, cis monomer produces an amorphous polymer, and it is a mixture of threo- and erythro-di-isotactic structure. From these results, it is concluded that the double bond in trans monomer is opened exclusively in the cis type, and in cis monomer cis- and trans-openings take place at almost the same rate.