Preparation and Performance Study of Modified Graphene Oxide/Polyurethane Anti-Corrosion Coating

To address the corrosion and degradation of metallic materials in seawater, tidal, and similar environments, this study employs lysine (C6H14N2O2) to modify graphene oxide (GO) via a hydrothermal process. The modified graphene oxide (f-GO) and poly(l-lysine) (PL) composite was characterized structurally and functionally using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) to characterize its structure and properties. A composite coating was prepared using modified graphene oxide (f-GO) and polyurethane (PU), which underwent electrochemical testing, hardness testing, corrosion rate testing, adhesion testing, impact resistance testing, and salt spray corrosion resistance testing. Experimental results indicate that C-N stretching vibration peaks appeared at all reaction temperatures. At 85 °C, f-GO85 exhibited optimal modification with a layer spacing of 1.471 nm, 72% transmittance, and superior thermal stability, confirming successful lysine grafting onto the GO surface. Corrosion resistance testing of the composite coating revealed enhanced adhesion and impact resistance, reduced corrosion rate, decreased corrosion current density in polarization curves, positive shift in corrosion potential, and higher impedance values in impedance curves, indicating improved coating density and corrosion resistance. Salt spray tests demonstrated that incorporating lysine-modified graphene oxide significantly improved the anti-corrosion performance of polyurethane coatings. Optimal corrosion resistance was achieved when the modified graphene oxide content was 0.2 wt%.