Facile modification of graphene oxide with Lysine for improving anti-corrosion performances of water-borne epoxy coatings

Abstract To develop the compatibility of graphene oxide (GO) nanosheets with water-borne epoxy (EP) coatings, a natural amino acid with double amines (Lysine) was used to modify GO (LY-GO). Results obtained from Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) confirm that Lysine is successfully decorated on GO surface by formation of chemical bonds. Then LY-GO nanomaterials were introduced into EP coatings on the mild steel substrate. The SEM images demonstrate that distribution of LY-GO in EP coatings was remarkably improved due to Lysine modification. The effect of LY-GO and GO nanosheets on the anti-corrosion property of the EP coating was studied by potentiodynamic polarization test, electrochemical impedance spectroscopy (EIS), and salt spray test. Results reveal that well-distributed LY-GO nanosheets remarkably reinforce the anti-corrosion performance of the EP coatings. At the same filler content, LY-GO provides EP coating with better anti-corrosion property of than GO and the corrosion rate of LY-GO/EP coating is approximately two orders of magnitude lower than that of GO/EP. Moreover, LY-GO can also effectively decrease the coating delamination degree during salt spray test of 500 h.