Waterborne polyurethane coating based on tannic acid functionalized Ce-MMT nanocomposites for the corrosion protection of carbon steel

By encapsulating corrosion inhibitors in pH-responsive nanocontainers, the coating provides strong active protection against the aggressive environment, which is an effective way to develop highly efficient coatings. Here, tannic acid functionalized Ce-MMT nanocomposites were prepared and their effect on the anti-corrosion properties of waterborne polyurethane coating was investigated. Among them, the MMT plays the role of a physical barrier and a container; and Ce3+ as cathodic protectant. TA not only has the effect of anodic protection but also increases the dispersion of the nanocontainer. In a specific experiment, the anti-corrosion property of the composite coating was investigated by electrochemical. The results showed that WPU/TA@Ce-MMT coating had long-term anti-corrosion ability after soaking for 50 days, and the |Z|0.01Hz was two orders of magnitude higher than that of pure WPU. Also, the analysis of scratch coating demonstrated that Ce3+ and TA could serve as selfhealing agents to block the corrosion process when the corrosive medium reaches the metal/coating interface through artificial scratches. This novel synergistic anticorrosion system opens a new possibility for manufacturing high-efficiency anticorrosion coatings.

Automated summary

By encapsulating corrosion inhibitors in pH-responsive nanocontainers, highly efficient coatings that provide strong active protection against aggressive environments can be developed. This study investigated the effect of tannic acid functionalized Ce-MMT nanocomposites on the anti-corrosion properties of waterborne polyurethane coating. The results showed that the composite coating had long-term anti-corrosion ability and significantly higher impedance compared to pure waterborne polyurethane coating. Additionally, the analysis revealed that Ce3+ and tannic acid could act as self-healing agents to block the corrosion process when the corrosive medium reaches the metal/coating interface through artificial scratches.