Selective Anionic Polymerization of 2,5-Divinylthiophene Derivatives
Selective Anionic Polymerization of 2,5-Divinylthiophene Derivatives
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DOI：
10.1021/acs.macromol.1c01331
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发表时间：
2021-08
期刊：
影响因子：
5.5
通讯作者：
Raita Goseki;Ayaka Oguri;Yuki Kurishiba;Takashi Ishizone
中科院分区：
文献类型：
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作者：
Raita Goseki;Ayaka Oguri;Yuki Kurishiba;Takashi Ishizone
以低聚(α-甲基苯乙烯基锂)(αMSLi)和10倍过量的tBuOK为二元引发剂，在−78°C的四氢呋喃中，在2，5-二乙烯基噻吩基的一个乙烯基团上进行了选择性阴离子聚合，反应温度为78℃。2-异丙烯基-5-乙烯基噻吩基(IPrVT)是一种不对称的二乙烯基单体，在αMSLi/tBuOK的引发下也进行了选择性阴离子聚合，得到了具有可预测的相对分子质量(Mn<；9.0 kg/mol)和窄分子量分布(MW/mN<；1.15)的聚合物。在每种情况下，αMsLi/tBuOK的二元引发体系有效地防止了传播的阴离子与残留的乙烯基或异丙烯基团的副反应。所得聚合物(IPrVT)中残留乙烯基团的~1H核磁共振信号较弱(∼为5%)，而异丙烯基团为主导信号，表明iPrVT中的异丙烯基团也参与了聚合反应，但程度较小。得到的聚合物具有玻璃化转变温度(∼75°C)和典型的热交联放热峰(>；120°C)，证实了聚合物重复单元中残留的乙烯基团的反应性。
Selective anionic polymerization of 2,5-divinylthiophene was conducted at one of its two vinyl groups in a living manner using oligo(α-methylstyryllithium) (αMSLi) and a 10-fold excess oftBuOK as a binary initiator system in tetrahydrofuran at −78 °C. 2-Isopropenyl-5-vinylthiophene (iPrVT), an asymmetric divinyl monomer, also underwent selective anionic polymerization under the initiation of αMSLi/tBuOK to yield a polymer with a predictable molecular weight (Mn< 9.0 kg/mol)) and a narrow molecular weight distribution (Mw/Mn< 1.15). In each case, the binary initiator system of αMSLi/tBuOK effectively prevented the side reactions of the propagating anion with the residual vinyl or isopropenyl groups. A weak1H NMR signal (∼5%) of the residual vinyl groups was observed for the resulting poly(iPrVT) along with dominant signals of the isopropenyl group, suggesting that the isopropenyl group of iPrVT also participated in the polymerization but to a significantly lesser extent. The obtained polymers exhibited glass-transition temperatures (∼75 °C) as well as typical exothermic peaks (>120 °C) owing to thermal cross-linking, confirming the reactivity of the residual vinyl groups in the repeating unit of the polymer.