A User-friendly Living Cationic Polymerization: Degenerative Chaintransfer Polymerization of Vinyl Ethers by Simply Using Mixtures of Weak and Superstrong Protonic Acids
A User-friendly Living Cationic Polymerization: Degenerative Chaintransfer Polymerization of Vinyl Ethers by Simply Using Mixtures of Weak and Superstrong Protonic Acids
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DOI：
10.1007/s10118-019-2233-0
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发表时间：
2019-09
影响因子：
4.3
通讯作者：
Mineto Uchiyama;Masataka Sakaguchi;K. Satoh;M. Kamigaito
中科院分区：
文献类型：
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作者：
Mineto Uchiyama;Masataka Sakaguchi;K. Satoh;M. Kamigaito
采用弱质子酸和痕量超强质子酸的混合物，通过链转移机理简单控制乙烯基醚的阳离子聚合，其中弱质子酸作为链转移剂（CTA）的前体或休眠物种，超强质子酸作为阳离子增长物种的来源。加入磷酸三丁酯（（n-BuO）2 PO 2 H）或1-辛炔的混合物，（n-C8 H17 SH）和痕量的三氟甲磺酸（TfOH）加入到异丁基乙烯基醚（IBVE）的溶液中，在-78 °C下产生具有受控分子量的聚合物，其基本上由IBVE与弱质子酸的进料比确定，分子量分布窄（Mw/Mn ≤ 1.1）。这些结果与在类似条件下，在痕量TfOH存在下，使用它们制备的IBVE加合物作为CTA所获得的结果几乎相同。甲磺酸（CH 3SO 3 H），其IBVE的加合物由于不稳定性而未被分离，类似地与痕量TfOH结合使用，以产生受控的分子量，但稍微更宽的MWD（Mw/Mn= 1.2-1.8）。这些结果表明，氧化锍离子也是一个有效的中间体，在阳离子DT聚合除了磷和锍中间体衍生自（n-BuO）2 PO 2 H和n-C8 H17 SH，分别。因此，通过使用弱质子酸和微量TfOH的组合来实现简单的活性阳离子聚合，所述弱质子酸和微量TfOH均容易获得、低成本、不含金属且易于处理，而不需要制备引发剂。
Mixtures of a weak protonic acid and a trace amount of superstrong protonic acid were used for the simple control of the cationic polymerization of vinyl ethersviaa degenerative chain-transfer mechanism, in which the former acid works as a precursor of the chain transfer agent (CTA) or the dormant species and the latter works as a source of the cationic propagating species. The addition of mixtures of phosphoric acid dibutyl ester ((n-BuO)2PO2H) or 1-octanethiol (n-C8H17SH) and a trace amount of trifluoromethanesulfonic acid (TfOH) to a solution of isobutyl vinyl ether (IBVE) at −78 °C resulted in polymers with controlled molecular weights, which were basically determined by the feed ratio of IBVE to the weak protonic acid, and narrow molecular weight distributions (Mw/Mn≈ 1.1). These results were almost the same as those obtained using their prepared adducts of IBVE as CTAs in the presence of a trace amount of TfOH under similar conditions. Methanesulfonic acid (CH3SO3H), whose adduct of IBVE has not been isolated due to instability, was similarly used in conjunction with trace TfOH to result in controlled molecular weights but slightly broader MWDs (Mw/Mn= 1.2–1.8). These results indicate that the sulfoxonium ion is also an effective intermediate in the cationic DT polymerization in addition to the phosphonium and sulfonium intermediates derived from (n-BuO)2PO2H andn-C8H17SH, respectively. The simple living cationic polymerization was thus achieved by using a combination of a weak protonic acid and a trace amount of TfOH, which are both easily available, low cost, free from metal, and easy to handle, without need for preparation of the initiator.