高分子量聚碳硅烷合成研究

SYNTHESIS OF HIGH MOLECULE WEIGHT POLYCARBOSILANE

采用正交设计的方法从常压合成得到的中低分子量聚碳硅烷(PCS)出发,进行热压合成制备高分子量的PCS;并运用红外、GPC、核磁共振等分析测试手段对其结构和性能进行了表征.研究表明,采用从常压合成得到的中低分子量PCS出发进行热压合成的化学方法,可以制备得到高分子量的PCS;控制热压反应温度在460-470℃、预加压力1-2 MPa、反应6 h得到先驱体PCS的Mw在6400-8500之间;热压合成后制得的高分子量PCS的支化度有所降低;通过控制热压反应时间可以较好的调控高分子量PCS重均分子量的大小.

Polycarbosilane （PCS） of high molecule weight was a kind of important precursor for SiC fibers with low oxygen content. High molecule weight PCS was synthesized under high pressure by using PCS of low/middle molecule weight synthesized under normal pressure. The structure and performance of the products were characterized by means of FTIR, GPC and NMR measurements. PCS samples of weight overage molecular weight 6400- 8500 and less degree of branching were obtained. The suitable conditions for preparation are as follows： reaction time 6 h, Temperature 460 - 470 ℃ and pressure 1 - 2 MPa.