Role of precursor chemistry on synthesis of Si–O–C and Si–O–C–N ceramics by polymer pyrolysis

In this study, the role played by polymer precursor chemistry on the nature of the pyrolyzed product was examined. Variables examined included extent of conjugation of the precursor, differences between a homopolymer and co-polymer, linear and cyclic structures, siloxanes and silazanes and between vinyl and phenyl containing silanes. Results indicate increasing the vinyl content of the precursor increases the amount of free carbon in the pyrolyzed product. The introduction of an aryl group in the silane decreased yield and lastly there was no change in the yield when a silazane was used instead of a silane, however, the composition of the silazane precursor ceramic is rich in nitrogen while a silane precursor ceramic is rich in carbon.