An easy-to-process poly(silylene-acetylene) terminated by reactive ethynylphenyl: Synthesis, properties and composites

A series of telechelic silicon-containing hybrid polymers with reactive ethynylphenyl terminals were synthesized using the Grignard reagent method. The structure, processability, curing behavior, thermal stability and dielectric properties of the polymers, as well as the mechanical properties of carbon fiber reinforced composites at room temperature and high temperature, were well characterized. The results indicate that the ethynylphenyl-terminated poly(silylene acetylene)s (EPTSAs) have wide processing window and stable viscosity for 6 h at 70 °C. The cured EPTSAs exhibit excellent thermooxidative stabilities with temperatures of 5% weight loss ( T d5 ) and the residues at 800 °C ( Y r800 ). The thermal stability of the cured EPTSAs can increase markedly with incorporation of Si-H groups. The T d5 and Y r800 of the cured EPTSAs could reach to 601 °C and 52% in air, respectively. The pyrolysis behavior of cured EPTSAs elucidates the cure reactions and cross-linked networks. The cured resins show excellent dielectric properties in the frequency range of 10–10 6  Hz. Furthermore, the glass transition temperature of the cured EPTSAs do not arise before 500 °C. The flexural strength and modulus of the carbon fiber cloth (T300CF) reinforced EPTSAs composites could reach 252 MPa, and 42 GPa. The retention of mechanical properties of the composite at 300 °C can reach to 89%.