Synthesis and characterization of polyaluminocarbosilane as SiC ceramic precursor

Polyaluminocarbosilane（PACS） was synthesized by the reaction of aluminum acetylacetonate（（Al（AcAc）3）） with polysilacarbosilane （PSCS）, which was prepared by thermolysis and condensation of polydimethylsilane （PDMS）. The sublimation of Al（AcAc）3 could be avoided by the use of PSCS as reactant. The empirical formula of PACS was SiC2.01H7.66O0.13Al0.02, which has the relative molecular mass of 2 265. When the reaction of PSCS with Al（AcAc）3 proceeds, an enormous decrease in the number of Si—H bonds in PSCS is observed, at the same time, gas acetylacetonate is a by-product of the reaction based on the ligands of Al（AcAc）3. The reaction mechanism is found to be related to the increase in the molecular mass of PACS by the cross-linking reaction of （Si—H） bonds in PSCS with Al（AcAc）3, which leads to the formation of Si—Al bonds.