Significant promotion of the anti-corrosive performance of epoxy zinc-containing coating via in situ reduction of graphene oxide and simultaneous graft it with polyamide curing agent

Two different reduced graphene oxide, i.e. the chemical reduced GO grafted with the polyamide (PGO) and common thermal reduced graphene oxide (RGO), had been used to modify epoxy/Zn composite coatings and their anticorrosive behavior was studied and compared. PGO was innovatively incorporated into the epoxy composite coating during preparing the paint via the solve-thermal treatment of GO in polyamide-651 at 90 °C. Various analyses revealed that GO was reduced in situ and simultaneously grafted with polyamide macromolecules during the solve-thermal treatment. Compared to pristine GO and RGO, PGO displayed improved dispersibility in the resin diluent and its superior effect on improving the anti-corrosive performance of epoxy/Zn coating was confirmed by different corrosion test and surface analysis technique. Moreover, its optimum content in the composite paint was only 0.3 wt%. The excellent anti-corrosion performance of the composite coating could be attributed to the great barrier properties of PGO in the epoxy coating, as well as its good dispersion and compatibility to epoxy matrix.