| 초록 |
Polycarbosilane (PCS) is a well known preceramic polymer as a SiC precursor, which has been used for high temperature structural applications such as fiber, composites. However it was disadvantageous with relatively harsh reaction conditions using an autoclave above 400oC. In this study, PCS was synthesized from polydimethylsilane (PDMS) with the presence of various types of zeolites as catalysts at 350oC for 6hrs and followed by heating to 400oC for additional 6 hrs. The obtained products were mainly fractionated into the soluble solid part and the volatile low molecular weight part by heating at 250oC under a nitrogen atmosphere. The synthesized PCS parts were determined by TGA, FT-IR, GPC, 1H-NMR, 29Si-NMR analysis to investigate the effect of the catalyst on characteristics of the polymer. Moreover, the soluble solid part was simply melt-spun by hand-drawing method, followed by pyrolysisy at 1200oC to obtain a SiC fiber. And the low molecular weight part was post-treated in the presence of additive compounds to increase the molecular weight. |
