聚二甲基硅烷高温高压合成聚碳硅烷工艺研究  

Synthesis of Polycarbosilane from Polydimethylsilane atHigh Temperature and High Pressure

作　　者：程祥珍[1] 宋永才[1] 谢征芳[1] 肖加余[1] 王应德[1] 

机构地区：[1]国防科学技术大学航天与材料工程学院新型陶瓷纤维及其复合材料国防技术重点实验室,长沙410073

出　　处：《材料工程》2004年第8期39-43,共5页Journal of Materials Engineering

基　　金：国家自然科学基金资助项目 ( 5 0 0 82 0 0 7)

摘　　要：以聚二甲基硅烷 (PDMS)为原料 ,在高压釜内高温高压反应制备了聚碳硅烷 (PCS)先驱体 ,研究了合成条件对反应终压、 Si- H键含量、产物产率、软化点、分子量及其分布及可纺性的影响。研究表明 ,随着反应温度的提高 ,反应时间的延长 ,反应终压逐渐增大 ,产物的分子量与软化点增高 ,但同时分子量的分散性增大使可纺性变差。当 PDMS在高压釜内 4 6 0℃下反应 4～ 6 h,或 4 5 0℃下反应 6～ 7h时 ,可以制得软化点约为 2 0 0～ 2 2 0℃的 PCS,其高分子部分含量约 5 %～ 10 % (质量分数 ) ,Si- H键含量大于 0 .9,可纺性较好 ,适合于制备 Si C纤维。The polycarbosilane (PCS), the precursor of SiC fiber, was synthesized at high temperature and high pressure by thermal decomposition of polydimethylsilane (PDMS). The influence of synthesis conditions on final pressure at room temperature, Si-H bond content, PCS yield, softening point, the molecular weight and distributions, and spinnability were investigated. The results show that the molecular weight and softening point of PCS increase while the reaction temperature increase The spinnability of PCS decreases gradually with temperature. Suitable reaction time for the synthesis of PCS from PDMS in autoclave should be 4 - 6 h at 460°C, or 6 - 7 h at 450°C. The as-synthesized PCS, in which the high molecular weight content was about 5%-10% (mass fraction) with softening point about 200 to 220°C > Si-H bond content more than 0.9, and good spinnability, was the suitable precursor for the preparation of SiC fiber.

关 键 词：聚二甲基硅烷 聚碳硅烷 合成 

分 类 号：TQ343[化学工程—化纤工业]