【摘要】 在高温常压下,以聚二甲基硅烷(Polydimethylsilane,PDMS)和乙酰丙酮铝(Al(AcAc)3)为原料,合成了碳化硅(SiC)陶瓷纤维先驱体———聚铝碳硅烷(Polyaluminocarbosilane,PACS)。采用红外光谱法和凝胶渗透色谱法对制备的PACS进行了结构和分子量表征;通过正交实验设计,研究了反应温度、裂解温度、反应时间和原料配比4种因素对PACS的Si-H键含量、支化度和数均分子量Mn的影响,并用极差分析法进行了主次因素分析,结果表明反应温度是上述三指标的主要影响因素。综合分析各指标对PACS后续纺丝性能和高温碳化过程的影响,确定制备PACS较优的实验条件为:反应温度390℃、裂解温度490℃、反应时间10h及原料Al(AcAc)3与PDMS配比4%(质量分数)。更多还原

【Abstract】 SiC ceramic fiber precursor-polyaluminocarbosilane(PACS) was synthesized with polydimethylsilane(PDMS) and aluminium acetylacetonate(Al(AcAc)3) as raw materials at high temperature and ordinary pressure.The structure and molecular weight of PACS were characterized via the methods of infrared spectrum and gel permeation chromatography.The influence of four actors(reaction temperature,pyrolysis temperature,reaction time and the mixture ratio of raw materials) on the Si-H content,degree of branching and number average molecular weight Mn of PACS were studied via orthogonal experiment,the primary and secondary factors have been analyzed via the method of range analysis.The results showed that reaction temperature was the principal factor of the influence on the above three indexes.Consider with the factors′s influence on the following spinning property and high temperature carbonization of PACS,a better experiment condition of synthesizing PACS was obtained,that is: reaction temperature 390 ℃,pyrolysis temperature 490 ℃,reaction time 10 h and the mixture ratio of Al(AcAc)3 and PDMS 4wt%.更多还原