Synthesis and properties of chemically modified polycarbosilane containingorganofluoric groups

The chemically modified polycarbosilane (PC) containing organofluoric group s, PCOCF, was synthesized through chemical reaction of PC and fluoric alcoh ol. Pyrolysis of the polymer precursor occurred in three stages under 1000 degrees C, Weight loss due to evaporation of low molecular compounds was ob served at the first stage below 300 degrees C, followed by the largest weig ht loss from 300 to 600 degrees C at the second stage. At this stage, side chains formed during the chemical reaction were removed. Finally, side chai ns such as Si-CH3 decomposed at the third stage above 600 degrees C, At 100 0 degrees C, the chemical modification of PC resulted in high yield of soli d product. After coating PCOCF on silicon carbide (SiC) powders, the conver sion yield of pyrolyzed PCOCF was further improved due to the interaction b etween PCOCF and SiC powders. Coating of PCOCF on SiC powders was found to be effective in increasing the green density of uniaxially pressed bodies.