杂Diels-Alder环加成反应级联RAFT聚合

Cascade RAFT Polymerization of Hetero Diels-Alder Cycloaddition Reaction

Diels-Alder(DA)反应温度可逆、无需催化剂、高效快速且无有害产物,成为构建可自愈和可回收的动态共价弹性体网络的有利选择。然而传统的DA反应(比如呋喃和马来酰亚胺)存在反应时间长、反应温度高和模块化差等问题。近年来研究发现,具有高反应性的二烯可与特异性的RAFT试剂发生HDA反应(含杂原子硫的Diels-Alder环加成反应),实现HDA反应与RAFT聚合的高效级联,降低DA反应温度及反应时间的同时,又将RAFT聚合对于聚合物分子量以及分子量分布的精确可控性结合到DA反应中,在制备高分子量嵌段及接枝聚合物、表面修饰等方面有广泛的应用潜力。本文综述了近十五年来HDA-RAFT级联反应的研究与应用,探讨了目前仍存在的一些问题和解决方法,并对未来这一领域的发展进行了展望。

Diels-Alder(DA)reaction is temperature-reversible,catalyst-free,efficient and fast with none harmful products,making it a favorable choice to build a self-healing and recyclable dynamic covalent elastomer network.However,classic DA reactions(such as the reaction between furan and maleimide)still have the problems of long reaction time,low efficiency and poor chemical modularity.Recent studies have shown that the efficient cascade of HDA reaction(Diels-Alder cycloaddition reaction containing heteroatom sulfur)and RAFT polymerization can be realized by highly reactive dienes reacting with specific RAFT agents,which can reduce the reaction temperature and time of DA.By virtue of the RAFT polymerization,it can control polymer molecular weight and its distribution at the same time.RAFT-HDA cascade reaction shows wide potential applications especially in the preparation of high molecular weight block or grafted polymer and surface modification.In this paper,the research and application of HDA-RAFT cascade reaction in the past 15 years are summarized,existing problems and solutions are discussed and the future development of this field is also prospected.