Synthesis via pyrolysis and characterization of si-c-o ceramics from 1,4-butanediol and methyltriethoxysilane

Si-C-O ceramics were prepared by the interchange reaction of methyltriethoxysilane (NITES) with 1,4butanediol (BD) and the subsequent pyrolysis. The structures of gels before and after pyrolysis were analyzed by NMR and 1R. Carbon-13 CP/MAS NMR spectrum of the gel indicated the interchange reaction with the ethoxy groups of precursor, MTES. Silicon-29 MAS NMR spectra of the pyrolyzed gel revealed that SiC2O2 and SiC4 units existed upon higher temperature heat treatment. The cleavage of BD and the formation of free carbon phase in the pyrolyzed products were certified through TG-MS and C-13 MAS NMR. Si-29 MAS NMR, IR and XRD indicated the reaction of the free carbon with silica to form beta-SiC above 1300degreesC.