基于Grignard偶合法合成液态超支化聚碳硅烷

Synthesis of Liquid Hyperbranched Polycarbosilane Based on Grignard Coupling Method

液态超支化聚碳硅烷(Liquid Hyperbranched Polycarbosilane,LHBPCS)作为一种纤维增强Si C陶瓷基复合材料的先驱体,因具有流动性好、可自交联、陶瓷产率高以及热解产物接近Si C化学计量比等优点而备受关注。在多种制备LHBPCS的方法中,Grignard偶合法因操作简单、中间产物不需要提纯、原料成本较低且可以采用多种原料混合的方法对LHBPCS的组成和结构进行调控以得到性能优越的Si C陶瓷先驱体而成为研究的热点和方向。论文对基于Grignard偶合法合成LHBPCS以及LHBPCS后续的交联和陶瓷化等工艺的主要研究进行综述,并展望今后的发展。

As one of precursors of fiber-reinforced Si C ceramic matrix composites,liquid hyperbranched polycarbosilane（LHBPCS）has received great attention due to its good fluidity,self-crosslinking,high ceramic yield and the ratio of Si to C in pyrolytic product approaching Si C stoichiometry etc.In a variety of ways of synthesizing LHBPCS,Grignard coupling method has become the focus and direction of research,because its procedures are readily handled,the intermediates needn＇t be purified,the raw materials are commercially available cheap,and the composition and structure of LHBPCS could be adjusted through changing raw materials and their feed ratio.In this paper,the synthesis of LHBPCS based on Grignard coupling method and the subsequent crosslinking and ceramization processes of LHBPCS were summarized and the prospects of LHBPCS were also proposed.