Corrosion resistance of a self-curing waterborne epoxy resin coating

Waterborne coatings have gained more and more attention as a method to protect the environment. However, the application of waterborne coatings to metals, especially for sufficient long-term protection in harshly corrosive environments, is still limited. Here, we report a self-curing waterborne coating with good corrosion resistance. First, a self-curing waterborne epoxy resin (SWEP) was synthesized by a chemical reaction between the epoxy resin and titanium diisopropoxide bisacetylacetonate in water. The structural characterizations via Fourier transform infrared spectroscopy and 13C nuclear magnetic resonance spectrsocopy confirmed the successful preparation of the SWEP resin. Differential scanning calorimetry and thermogravimetric analysis showed that the SWEP resin could be cured by heating without the use of any curing agents, and the cured coating exhibited good thermal resistance. The mechanical properties of the cured coatings were discussed in the context of the corresponding standards. The results confirmed that the physical properties of the SWEP coating were as good as those of a traditional two-component waterborne epoxy resin (DCWEP) coating. The chemical resistance analysis revealed that the water, acid and alkaline resistances of the SWEP coating all have significant improvements compared to those of the DCWEP coating. The electrochemical impedance spectroscopy and potentiodynamic polarization test implied that the SWEP coating provided better corrosion protection for metal substances than the DCWEP coating.