基于自加速点击反应的高分子合成新方法

Polymer chemistry originates from organic chemistry. Introduction of the new organic reactions to ingeniously fabricate the polymer chains is one of the key research topics in polymer chemistry. In this proposal, we are going to discover a library of novel self-accelerating click reactions by systemically investigating the [3+2] cycloaddition reactions between varied 1,3-dipoles and sym-dibenzo-1,5-cyclooctadiene-3,7-diyne derivatives. Based on this, we are going to develop the unique polymer synthetic methods by virtue of these novel self-accelerating click reactions to replace the regular reactions with equal reactivity of reactive groups widely used in traditional polymer synthetic methods. In step-growth polymerization, we are going to develop a series of novel stoichiometric imbalance-promoted step-growth polymerization methods using the self-accelerating click reactions as coupling reactions. These novel approaches avoid the requirement of strict stoichiometry of AA and BB type monomers in traditional step-growth polymerization for the formation of high molecular weight polymers. Alternatively, they can use stoichiometry imbalance to speed up the polymerization and efficiently produce polymers with high molecular weight (> 5×10⁵ g/mol) in a very mild reaction condition. In addition, we are going to explore the self-accelerating click reactions to prepare topological polymers. The stoichiometric imbalance-promoted step-growth polymerization is used to prepare high molecular weight sequence-controlled polymers with varied reactive groups. Using them as polymer main chains to graft different kinds of polymer side chains, we are going to develop a novel technique to prepare the bottlebrush polymers with different kinds of polymer side chains in a strictly ordered sequence. Using the self-accelerating click reactions to polymerize AB₂ type monomers, we are going to develop a convenient, clean, and efficient “one-pot” method for the formation of hyperbranched polymers with a high degree of branching (≈ 1).

有机化学是高分子化学发展的源泉，发现新的有机化学反应并将其巧妙应用于高分子链的构筑是高分子合成化学的核心研究内容之一。本项目拟通过研究各类1,3-偶极子和二苯并环辛二炔类化合物的[3+2]环加成反应，建立新颖的自加速点击化学反应库。基于此，将以该类自加速点击反应替代传统高分子合成方法中的等活性基元反应，发展高分子合成新方法。在逐步聚合领域：发展基于该自加速点击反应的AA-BB型逐步聚合新方法，消除传统方法中官能团等当量要求对合成高分子量聚合物的制约，实现利用官能团不等当量、在温和条件下、高效合成绝对分子量大于50万的聚合物。在拓扑高分子合成领域：以该新型逐步聚合法合成多种官能团序列精确排列的高分子量反应性高分子，以其为主链发展具有多种侧链精密排列的刷状高分子合成新方法；以该自加速点击反应聚合AB₂单体，建立“一锅”合成高支化度（≈1）超支化高分子的简单、清洁、高效合成新方法。

建立了苯并环辛二炔基自加速点击反应库，研究发现苯并环辛二炔与叠氮、悉尼酮、硝酮等各类1,3-偶极子的环加成反应均表现出自加速点击反应特性，其中苯并环辛二炔的第一个张力炔基与1,3-偶极子反应后原位活化第二个未反应张力炔基，其与1,3-偶极子的反应速率常数是未活化炔基的200倍左右。系统研究了该类型自加速点击反应在逐步聚合和环形高分子合成领域的应用，发展了不等当量促进的逐步聚合和双分子关环合成环形高分子新方法。以苯并环辛二炔和两官能度1,3-偶极子化合物为单体组合，逐步聚合均可在苯并环辛二炔过量情况下快速生成高分子量聚合物，消除了传统逐步聚合对官能团等当量的苛刻要求，此外多样的1,3-偶极子种类还赋予了所得聚合物多样的物理化学性能。以苯并环辛二炔为小分子连接子关环双叠氮末端线性高分子前驱体，可在苯并环辛二炔过量情况下快速合成各类高纯度环形高分子，辅以慢滴加的投料方式，发展了双分子关环大量合成环形高分子方法。