Effect of Electron Beam Irradiation in Air on Chemical Structure  and Pyrolysis Properties of Polycarbosilane Precursor Fibers

Polycarbosilane(PCS) precursor fibers were irradiated by 10 MeV electron beam in air atmosphere. Chemical structure, gel content, pyrolysis properties, and tensile strength were studied. Results show that bridge structures of Si—O—Si， Si—C—Si are formed in the irradiated products. Gel content， ceramic yield， and tensile strength are increased with the absorbed dose increasing. The fibers begin to form gel at a dose of 4.0 MGy. At the absorbed dose of 70 and 10.0 MGy， the gel content are 81% and 85%. The ceramic yield are 80.5% and 83.8%. The tensile strength are 1.7 GPa and 1.9 GPa， respectively.