Synthesis of polycarbosilane with a super high molecule weight and its characterization

By the orthogonal design strategy, PCS with a super high molecule weight was synthesized under high pressure from the PCS with a low/middle molecule weight synthesized under normal pressure. Through research by FT-IR, GPC and NMR, its' structure and performance were characterised. It was found that PCS with a super high molecule weight could be synthesized under high pressure from the PCS with a low/middle molecule weight synthesized under normal pressure. Suitable reaction time should be 6 hours at 460°C to 470°C and under 1 MPa to 2 MPa beforehand. Average molecule weight of the as-synthesized PCS was 6400 to 8500. Both its' degree of branching and the content of Si-H decreased. The average molecule weight of PCS with a super high molecule weight could be better adjusted by means of adjustment of reaction time.