Enhanced Anticorrosion Waterbased Polyurethane Coating Using Schiff Base Functionalized MXene

In this study, a novel anticorrosive waterborne polyurethane (WPU) coating was developed using Schiff base-functionalized MXene nanosheets. MXene (Ti3C2Tx) was first etched with hydrofluoric acid and then intercalated with a Copper (II) Schiff Base Complex Component (CSBCC), linked via (3-Aminopropyl) triethoxysilane (APTES) to enhance dispersion and chemical stability. The modified nanosheets (AMMXene-CSBCC) were incorporated into WPU at various weight fractions (0.3, 0.5, and 0.7 wt%) and applied to mild steel substrates. Characterization techniques, including FTIR, XRD, SEM-EDS, and TGA, confirmed the successful surface functionalization of MXene. Electrochemical Impedance Spectroscopy (EIS) results demonstrated that the optimal 0.5 wt% AMMXene-CSBCC coating (AXPU0.5) significantly improved corrosion resistance, achieving a total impedance of 6.9 × 107 Ω at 0.01 Hz after 48 h of immersion, compared to 7.6 × 105 Ω for pure WPU. Tafel polarization studies further revealed a reduction in corrosion current density to 6.04 × 107 A/cm2 for AXPU0.5, marking a 99.2 % inhibition efficiency, a notable enhancement over unmodified MXene-based coatings. The adhesion strength of AXPU0.5 was also improved, reaching 3.19 MPa, demonstrating strong substrate bonding. The Schiff base modification not only enhanced the oxidation resistance of MXene but also facilitated the formation of a more robust passive film, improving long-term protection. The superior anticorrosion performance, environmental benefits (reduced VOC emissions), and enhanced mechanical properties make this approach highly promising for industrial applications in marine, aerospace, and infrastructure sectors.