合成聚铝碳硅烷研究

Synthesis of Polyaluminocarbosilane

采用低分子量聚硅碳硅烷(polysilacarbosilane,PSCS)与乙酰丙酮铝(aluminum acetylacetonate,Al(AcAc)_3)在常压下反应来制备PACS。通过对不同阶段反应时间的调整,提高了数均分子量,得到了支化度低的Si-Al-C纤维的先驱体。研究表明,铝引入主要发生在第一阶段,延长第一阶段的反应时间有利于提高铝的保留率。Al(AcAc)_3的用量对Si-H含量有重要影响,随着其用量的增加,Si-H含量呈线性减小。

Polyaluminocarbosilane（PACS） is a precursor for ultra-high-temperature-resistance Si-C-Al fiber. In order to get the desired precursors for the fiber, polysilacarbosilane（PSCS） was reacted with aluminum acetylacetonate（Al（AcAc）3） to form PACS in N2 flow at ambient pressure. The synthesis was studied using various temperature programs. The PACS with high molecular weight, low polydispersity and good spinnability was finally obtained. It is found that aluminum was introduced mainly in the initial stage of the reactions. A longer reaction time during the first stage of reactions facilitated aluminum incorporation in PACS. The incorporation of Al occurred via the reaction of Al（AcAc）3 and Si-H bonds. Al（AcAc）3 reduced the content of Si-H bonds in PACS.