Chemical structures and pyrolysis properties of polycarbosilane irradiated by electron beam

Polycarbosilane (PCS) was irradiated by electron beam (EB) with inert gas protection. The as-prepared specimens were characterized using IR, Gel content measurements and TG-GC-MS. The chemical structures, the pyrolysis properties and the effects of irradiation dose were investigated. The result shows that three-dimensional netlike gel products composed as SiCSi crosslinking bonds were formed in the irradiated products, and that SiH bonds and CH bonds were partly broken down in the process of irradiation. The gel content of PCS increased evidently with the irradiation dose, especially when the absorbed dose was above 3 MGy. Furthermore, the thermo-stability and ceramic yield could be improved by EB radiation and the ceramic yield of PCS irradiated under 20 MGy could be up to 87%. In addition, the gel content, the pyrolysis temperature and the ceramic yield of pre-heatment at 400 ℃ could be higher than the PCS raw material at the same absorbed dose.