Preparation and Performance Study of Carboxy-Functionalized Graphene Oxide Composite Polyaniline Modified Water-Based Epoxy Zinc-Rich Coatings

Abstract

Graphene oxide is obtained by oxidation of graphite followed by ultrasonic exfoliation. It is a two-dimensional layered material with a large number of oxygen-containing functional groups on its surface. Polyaniline is a conductive polymer and has a unique corrosion protection mechanism. In this study, carboxy-functionalized graphene oxide/polyaniline (CGO/PANI) composites with a lamellar structure were prepared by in situ polymerization. The lamellar layer was used to form a labyrinthine structure in the coating to effectively retard the penetration of corrosive media. The electrical conductivity of polyaniline can promote the formation of conductive pathways between zinc particles and improve the utilization of zinc powder. Polyaniline is also able to passivate the substrate, further improving the coating’s ability to protect steel substrates against corrosion. In this paper, the in situ polymerization of aniline on carboxy-functionalized graphene oxide flakes was confirmed by scanning electron microscopy (SEM), Fourier infrared spectroscopy (FT-IR), and X-ray diffraction (XRD), and the improvement of the corrosion resistance of the prepared composites on the epoxy zinc-rich coatings was evaluated by SEM, electrochemical impedance spectroscopy (EIS), and salt spray resistance tests. The results showed that aniline was successfully polymerized in situ on carboxy-functionalized graphene oxide, and the modified coating had significantly improved anticorrosive properties, where the best anticorrosive improvement was achieved when CGO: PANI = 0.03.