Mechanical-induced functionalization of graphene with sodium carboxymethyl cellulose toward enhancing anticorrosion performance of waterborne epoxy coatings

Non-covalent modification of graphene is prepared by sodium carboxymethyl cellulose via ball milling. Adsorption and thermogravimetric analyzer (TG) indicate interaction of graphene with sodium carboxymethyl cellulose. Particle size and zeta potential results show sodium carboxymethyl cellulose with high DS play more role in assisting stabilization of graphene dispersion. The adsorption of sodium carboxymethyl cellulose onto graphene is inhibited under acidic conditions and the dispersion stability deteriorates sharply. Under neutral and alkaline conditions, the dispersions maintain stable. Embedding a small percentage of well-dispersed graphene nanosheets (CGr1.5%) in waterborne epoxy coating has remarkably improved anticorrosion performance, which is attributed to the synergistic effects of barrier properties of well-dispersed graphene nanosheets and CMC in the epoxy matrix. Open circuit potential (OCP), Tafel and electrochemical impedance spectroscopy (EIS) analysis confirmed that the corrosion rate exhibited by composite coatings with 1.5 wt% graphene is lower than that of neat epoxy coating.