Synthesis and pyrolysis of oligo(methylsilylene)-ethynylene polymer to near-stoichiometric SiC ceramic

Oligo(methylsilylene)-ethynylene polymer with crosslinkable ethynyl unit in the main chain was synthesized by condensation of α,ω-dicholorooligo(methylsilane) with dilithioacetylene. The as-synthesized polymer was characterized by GPC, FT-IR and NMR. The results showed ethynyl group was successfully introduced to the polymer main chain. The ceramic yield was dramatically increased by the cross-polymerization of ethynyl group, and the excess silicon of PMS was compensated. Near-stoichiometric (C/Si = 1.17) and partial crystallization β-SiC monoliths were obtained by pressureless pyrolysing PSPA at 1200 °C in a high yield (73.6 wt%).