Effect of silica-loaded polydopamine-modified graphene oxide nanocomposites on the corrosion resistance of polyester coatings

On the basis of the complex environment of port terminals, the corrosion resistance of coatings for accompanying metal facilities is a primary factor that needs to be considered. This study prepared polydopamine-modified graphene oxide loaded with silicon dioxide (PGO@SiO₂) functional filler, which was incorporated into polyester resin (PR) by extrusion mixing. The PGO@SiO₂/PR composite coating was obtained by electrostatic spraying and high-temperature curing. Fourier transform infrared spectroscopy, x-ray diffraction, and other results confirmed the successful preparation of the PGO@SiO₂ functional filler. In addition, contact angle, adhesion, and corrosion resistance tests were performed on the composite coating. Compared with pure PR coating, the surface hydrophobicity and adhesion of the composite coating were significantly improved compared with the pure PR coating. Furthermore, the electrochemical impedance spectroscopy of the carbon steel substrate composite coating confirmed that after immersion in salt solution, the low-frequency impedance modulus of the composite coating could be maintained at 8.63 × 10⁸ Ω·cm², which was more than two orders of magnitude higher than that of the pure PR coating. Thus, PGO@SiO₂ could significantly enhance the corrosion resistance of the PR coating and hinder the infiltration of corrosive media. It has broad prospects for engineering applications because of its excellent anticorrosive performance.