Enhanced interfacial properties of carbon fiber reinforced polyamide 6 composites by grafting graphene oxide onto fiber surface

•Graphene oxide (GO) was successfully grafted onto carbon fiber (CF) surface using hexamethylene diisocyanate (HDI) tripolymer as the coupling agent, obtaining GO modified CF (CF-g-GO).•The interfacial shear strength (IFSS) of CF-g-GO/PA6 composites increased by 40.2% compared with that of unmodified CF/PA6 composites.•The improvement of the interfacial properties of the CF-g-GO/PA6 composites is mainly attributed to the combined effects of the better wettability and the mechanical locking.