含硅重元素类烯烃化合物的缪子自旋共振及其自由基聚合探索

通用烯类聚合物材料因易燃、不耐高温、难降解等影响着人类的生存与可持续发展。含硅重元素类烯烃化合物的自由基聚合有望在工业上实现新型、特种高分子材料用于替代传统高分子材料。通过单体自由基的表征理解自由基聚合的微观动力学聚合机理对含硅重元素类烯烃化合物的工业应用具有重要意义。然而到目前为止，单体自由基的研究具有难度和局限性。本申请拟通过缪子自旋共振技术，在研究发现基团取代效应会影响含硅重元素类烯烃化合物形成自由基种类和特征的研究基础上，拟合成一系列不同位阻和电子效应取代的非环硅碳烯和硅膦烯化合物，结合理论计算系统研究这类化合物的取代结构与其形成自由基种类特征的关系，深入理解该类单体的自由基聚合机理，进一步研究其在有规立构自由基聚合中的应用。通过该项目的研究，有望推进中国在缪子自旋共振技术上的发展，引领缪子自旋共振技术在高分子科学难题中的新应用，实现含硅重元素类烯烃化合物在自由基聚合中的工业应用。

Due to the flammability, modest thermal stability and long-term impact on account of low biodegradability of the currently widely used polyolefin-based materials, their use affects the survival and sustainable development of mankind. Polymers based on the silicon-containing heavy analogues of alkenes are expected to potentially replace the traditional polymers to introduce a wide range of novel highly specialized polymeric materials. Synthesis of such polymers usually relies on radical-initiated polymerization of appropriate monomers. It is thus of great significance to develop a detailed understanding of the polymerization mechanism of such radical-initiated polymerizations through the characterization of radicals formed upon radical initiation of the silicon-containing heavy analogues of alkenes. However, so far, the traditional study of free radicals is difficult and has limitations. Based on our previous work that employs muon spin resonance, we could demonstrate that substituents have the influence on the species and characteristics of radicals formed by the silicon-containing heavy analogues of alkenes. In this project, we will synthesize a series of acyclic silenes and phosphasilenes (monomers) with substituents of different bulk and electronic effect and study their radicals via muon spin resonance in combination with the computational methods. We further intend to explore the relationship between the monomers’ structures and initiating radicals’ characteristics, to obtain a deeper understanding of the underlying mechanisms of the stereoregular radical-initiated polymerization of such monomers. This project is expected to promote the development of muon spin resonance technique in China, open new research avenues for the muon spin resonance in solving polymer science-related problems, and realize its potential and utility in the area of the industrial application of radical-initiated polymerization of silicon-containing heavy analogues of alkenes.