Living Cationic Polymerization of a Coumarin-Substituted Vinyl Ether and Reversible Photoinduced Cross-linking of the Resulting Homopolymers and Amphiphilic Block Copolymers
Living Cationic Polymerization of a Coumarin-Substituted Vinyl Ether and Reversible Photoinduced Cross-linking of the Resulting Homopolymers and Amphiphilic Block Copolymers
复制标题
香豆素取代的乙烯基醚的活性阳离子聚合以及所得均聚物和两亲性嵌段共聚物的可逆光致交联
DOI：
10.1002/pola.24918
复制
发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Jin Motoyanagi
中科院分区：
文献类型：
--
作者：
W.Chaikittisilp;A.Sugawara;A.Shimojima;T.Okubo;前田壮志;Jin Motoyanagi
以SnCl 4为单体，nBu 4 NBr为加成盐，在0 °C下进行了4-甲基-7-（2-乙烯氧基乙氧基）香豆素（CMVE）的活性阳离子聚合。所得聚合物的数均分子量与单体转化率成正比地增加，同时保持相对低的多分散性。结构分析表明，所得聚合物进行侧基香豆素基部分。通过用λmax= 366 nm的UV光照射使这些香豆素基部分交联，然后通过用λmax= 254 nm的UV光照射使交联位点裂解。通过紫外光谱和红外光谱研究了聚合物的交联行为。PolyCMVE可溶于二氯甲烷，但发现在UV光照射后不溶。我们还合成了两亲性嵌段聚合物轴承香豆素基团的活性阳离子共聚与两亲性乙烯基醚。所得嵌段聚合物可溶于水性介质中，并且还形成胶束状聚集体。在高于临界胶束浓度的水溶液的UV照射后，发生有效的交联反应。进一步研究了这些聚合物聚集体在溶液状态下的光致结构变化。© 2011 Wiley Periodicals，Inc.聚合物科学杂志A部分：聚合物化学，2011年
Living cationic polymerization of 4‐methyl‐7‐(2‐vinyloxyethoxy)coumarin (CMVE) was achieved using SnCl4in the presence ofnBu4NBr as an added salt at 0 °C. The number‐average molecular weight of the resulting polymers increased in direct proportion to the monomer conversion while retaining relatively low polydispersity. Structural analysis revealed that the resulting polymers carried pendant coumarinyl moieties. These coumarinyl moieties were crosslinked by irradiation with UV light at λmax= 366 nm, and the crosslinked sites were then cleaved by irradiation with UV light at λmax= 254 nm. The crosslinking behaviors of the polymers were studied by UV and FTIR spectroscopic measurement. PolyCMVE was soluble in dichloromethane but was found to be insoluble upon UV light irradiation. We also synthesized amphiphilic block polymers bearing coumarinyl moieties by living cationic copolymerization with an amphiphilic vinyl ether. The resulting block polymers were soluble in an aqueous medium and also formed micelle‐like aggregates. Upon UV irradiation of aqueous solutions above the critical micelle concentration, an efficient crosslinking reaction occurred. Photoinduced structural changes of these polymer aggregates in the solution state were further investigated. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011