One-pot synthesis of structure-controlled temperature-responsive polymer gels
One-pot synthesis of structure-controlled temperature-responsive polymer gels
复制标题
一锅法合成结构控制的温度响应聚合物凝胶
DOI：
10.1039/d2cc02651a
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发表时间：
2022
影响因子：
4.6
通讯作者：
Yukikazu Takeoka*
中科院分区：
文献类型：
--
作者：
Tomoki Sakai;Nagisa Ito;Mitsuo Hara;Takahiro Seki;Mineto Uchiyama;Masami Kamigaito;Kotaro Satoh*;Taiki Hoshino;Yukikazu Takeoka*
同时使用金属路易斯酸和二硫酯的光自由基产生剂（阳离子和自由基聚合的常见休眠物质）使得在光照射下将阳离子物质转化为自由基成为可能。在本研究中，我们尝试利用在黑暗中进行阳离子聚合制备的温度响应性遥爪聚合物，然后在光照射下机械转化为自由基交联反应，尝试一锅法合成具有受控网络结构的温度响应性聚合物凝胶。具体而言，在交联剂（己二酸二乙烯基酯）存在下，使用乙烯基醚型双功能RAFT试剂作为引发剂、路易斯酸（Et3Al2Cl3）和光自由基产生剂（TPO）在4℃下在甲苯中进行2-（2-乙氧基）乙氧基乙基乙烯基醚（EO2）的聚合。通过考虑通过阳离子聚合获得的远爪聚合物的分子量控制和重叠浓度，详细研究了光照射自由基聚合的凝胶化条件。结果，小角X射线散射表明，与通过常规自由基聚合获得的聚合物凝胶的交联网络相比，可以获得具有相对均匀的网络结构的聚合物凝胶。
The simultaneous use of metal Lewis acids and photo-radical generators for dithioesters, which are the common dormant species for cationic and radical polymerization, made it possible to convert a cationic species into a radical upon photoirradiation. In this study, we attempted one-pot synthesis of temperature-responsive polymer gels with controlled network structure by using temperature-responsive telechelic polymers prepared by cationic polymerization in the dark followed by the mechanistic transformation into radical cross-linking reaction under photoirradiation. Specifically, the polymerization of 2-(2-ethoxy)ethoxyethyl vinyl ether (EO2) in the presence of a crosslinking agent (divinyl adipate) was performed at 4 °C in toluene using a vinyl ether-type bifunctional RAFT reagent as initiator, a Lewis acid (Et3Al2Cl3) and a photo radical generator (TPO). The conditions for gelation by radical polymerization with photoirradiation were investigated in detail by considering the molecular weight control and overlapping concentration of the telechelic polymers obtained by cationic polymerization. As a result, small-angle X-ray scattering revealed that polymer gels with a relatively uniform network structure can be obtained compared to the cross-linked network of polymer gels obtained by conventional free-radical polymerization.