Research on the Corrosion Resistance of Waterborne Epoxy Resin Coating Enhanced by Sodium Alginate-Modified Ti₃C₂T<i>_x</i>

The enhancement of dispersion stability and interfacial compatibility of nanomaterials within aqueous epoxy matrices represents a pivotal strategy for augmenting the protective performance and corrosion resistance of coatings. In this study, Ti₃C₂T<i>_x</i> Mxene functionalized with sodium alginate (TSA) was obtained by introducing sodium alginate (SA) into Ti₃C₂T<i>_x</i> Mxene (T) to improve the corrosion resistance of aqueous epoxy coatings (EP). The dispersion stability of TSA in aqueous medium was quantitatively assessed via ζ-potential measurements, revealing a significant enhancement in stability compared to the reference material T. The long-term stability of TSA/EP composite coatings was systematically evaluated via electrochemical impedance spectroscopy (EIS). Notably, the charge transfer resistance (<i>R</i>_c) remained at 5 × 10⁷ Ω·cm² after a 60-day accelerated aging test, exhibiting exceptional electrochemical durability. Compared with pure EP coating, this value is improved by 2 orders of magnitude. The improvement is attributed to the fact that active -COOH and -OH groups on the surface of SA enhance the interactions between T nanosheets and EP matrix. Specifically, these functional groups form hydrogen bonds or chemical bonds at the interface. Such interfacial bonding mechanisms enhance the compatibility and interfacial adhesion between T and the EP matrix. These conclusions are further supported by manual scratching experiments. The accessibility and greenness of SA provide a simple and environmentally friendly way of thinking for modifying T.