采用聚硅碳硅烷与乙酰丙酮铝合成聚铝碳硅烷的机理  

Production mechanism of polyaluminocarbosilane using aluminum acetylacetonate with polysilacarbosilane

作　　者：赵大方[1] 李效东[1] 郑春满[1] 胡天娇[1] 

机构地区：[1]国防科技大学陶瓷纤维及其复合材料重点实验室,长沙410073

出　　处：《北京科技大学学报》2007年第2期130-134,共5页Journal of University of Science and Technology Beijing

基　　金：国家自然科学基金资助项目(No.59972042)

摘　　要：聚铝碳硅烷是耐超高温Si—Al—C纤维的先驱体.为了制备合适的先驱体,采用聚硅碳硅烷与乙酰丙酮铝反应合成聚铝碳硅烷,并对其反应机理进行了详细的研究.其中聚硅碳硅烷是含有Si—Si—Si和Si—C—Si的低聚物.通过在反应过程中从反应体系中抽取样品,并采用FTIR、GPC、1H-NMR、27Al-NMR和紫外可见光谱对反应过程进行追踪分析.结果表明:反应过程中存在Si—Si—Si向Si—C—Si转化的Kumada重排反应;乙酰丙酮铝的交联作用使得聚铝碳硅烷的相对分子质量和支化度大大提高,乙酰丙酮铝的反应主要发生在330℃以下和400℃以上,反应产物中Al以Si—O—Al结构存在.Polyaluminocarbosilane （PACS） is a precursor of ultra-high-temperature-resistance Si--Al--C fiber. In order to get a desirable precursor of the fiber, polysilacarbosilane （PSCS） was used to react with aluminum acetylacetonate （Al（acac）3） to get PACS, the reaction process was traced by FTIR, GPC, ^1H-NMR, 27 Al-NMR and UV-Vis spectra, and the production mechanism was studied in detail. The result shows that PSCS is a kind of oligomers with Si--Si--Si and Si--C--Si bonds. There are two kinds of reactions during the whole process. One is Kumada rearrangement that Si--Si--Si bond translated into Si--C--Si bond, the other is Al（acac）3 with the silicon carbon compounds. The obtained PACS has a higher relative molecular mass and branching degree because of the cross linkage of Al（acac）3. The crosslink mainly occurs below 330 ℃ and above 400 ℃. In PACS, Al is in the state of Si-O-Al.

关 键 词：聚铝碳硅烷 合成机理 碳化硅纤维 乙酰丙酮铝 

分 类 号：TQ314[化学工程—高聚物工业]