Modification of graphene oxide with acrylate phosphorus monomer via thiol-Michael addition click reaction to enhance the anti-corrosive performance of waterborne epoxy coatings

To develop a convenient way to functionalize graphene oxide (GO) for corrosion protective coatings, a commercial acrylate phosphorus functional monomer (SIPOMER PAM100) was used to modify thiol-terminated GO via thiol-Michael addition click reaction. Subsequently, PAM100 modified GO (PGO) was introduced to waterborne epoxy coating as a nanofiller for anticorrosion reinforcement. The anticorrosive performance of PGO/WEP nanocomposite coatings was evaluated by electrochemical impedance spectroscopy (EIS). Results obtained from FT-IR, XRD, Raman, SEM and SEM-EDS show that PAM100 is successfully grafted to the surface of GO using γ-Mercaptopropyl triethoxysilane (KH-580) as a bridge molecule. It is clear that PGO distributes homogenously within WEP matrix from SEM images. After 40-day exposure to 3.5 wt.% NaCl solution, the |Z|0.01Hz of blank WEP suffers a serious decrease (from 9.83 × 107 Ω·cm2 to 4.93 × 106 Ω·cm2) while PGO/WEP has a relatively smaller change in |Z|0.01Hz (from 1.35 × 108 Ω·cm2 to 2.91 × 107 Ω·cm2). It demonstrated that PGO/WEP coating presents a superior corrosion resistance performance.