Effects of coating structures on interfacial properties of carbon fibre/polyarylacetylene composites

Carbon fibres (CF) were modified with different coatings, including vinyltrimethoxysilane (VMS) and vinyl-silsesquioxane (VMS-SSO). VMS-SSO was obtained by the sol-gel hydrolytic condensation of VMS. The structure of VMS-SSO was characterised by FT-IR, NMR (¹H, ¹³C and ²⁹Si) and UV-MALDI-TOF MS. The VMS-SSO included several structures such as cage, semi-cage and ladder. Interlaminar shear strength (ILSS) and interfacial shear strength (IFSS) were measured to evaluate the effects of the coating structure on the interfacial properties of carbon fibre/ polyarylacetylene (CF/PAA) composites. The ILSS and IFSS of CF/PAA composites treated with VMS and VMS-SSO coatings showed that VMS-SSO coating had a better treatment effect than VMS. The fracture surface of the CF/PAA composites treated with different coatings was observed by SEM. The complex structures of the VMS-SSO seem to be the main reason for the different degrees of improvement in the interfacial adhesion.