Thermal stability of the copolymers of silicon-containing arylacetylene resin and acetylene-functional benzoxazine

Acetylene-functional benzoxazine resin (AFBEN) was used to modify silicon-containing aryacetylene resin (SCAAR). The thermal stability, degradation and ablation mechanisms were investigated. Based on the results of Py/GC/MS methods, we concluded that the cross-linking reactions of poly(dimethylsilyleneethynylene-phenyleneethynylene)(DMSEPE, a class of SCAAR) were due to (1) the Diels-Alder reaction between Ph-CC and CC, (2) the ring trimerization of CC and (3) radical polymerization of CC to form polyene structure. During the curing of AFBEN, polyene was the main product of the polymerization of ethynyl in AFBEN and the activation of the para positions of the aniline ring increased due to the introduction of ethynyl. XRD and XPS results showed that SiO2 and SiC formed on the surface of the composites in the process of ablation.