聚碳硅烷纤维化学气相交联研究

以环己烯作为反应气氛,对聚碳硅烷(PCS)纤维进行了化学气相交联不熔化处理。与空气不熔化进行对比,研究了不熔化过程中PCS纤维的反应程度及凝胶含量的变化,并进行了元素分析和热重差热分析,初步探讨了PCS纤维环己烯化学气相交联反应的机理。结果表明,在环己烯气氛中,PCS分子结构中Si-H键的反应程度随不熔化温度的提高逐渐增加,相应地,PCS纤维的凝胶含量迅速提高直至不熔。环己烯受热后产生自由基,引发PCS分子中的Si-H和Si-CH3键断裂形成自由基,促进PCS分子间形成Si-CH2-Si结构而实现交联。

Study on Chemical Vapor Curing Method for Polycarbosilane Fiber

Chemical vapor curing(CVC) method for polycarbosilane(PCS) fiber with unsaturated hydrocarbon vapor,cyclohexene,was studied and compared with air oxidation curing method.The analysis of composition and thermogravimetry of PCS fiber in the process of CVC was also characterized and an elementary reaction mechanism was discussed.The results show that Si-H bond in the molecular structure of PCS reacted during the cyclohexene curing process and the reaction degree increased with the rise of the curing temperature.Simultaneously,gel content of PCS fiber rapidly increased till PCS fiber became infusible.Si-H bond and Si-CH_3 bond broke and formed free radicals through the agency of cyclohexene radical while being heated up,and then formed the structure of Si-CH_2-Si,resulting in cross-linking between PCS molecules.