Enhanced corrosion resistant, tribological properties and self-healing of epoxy-polyurethane coatings by dynamic Diels-Alder bond

Epoxy resin is a class of thermosetting polymer widely used in high performance protective coating due to its excellent physical and chemical properties. However, its inherent brittleness, along with difficulties in self-healing and recycling, limits its application. In this study, an epoxy resin coating was modified by the combination of Diels-Alder (DA) dynamic reversible bond and soft polyurethane segment. The DA bonds endowed the coating with the ability to repair damage and to be reprocessed, while the polyurethane chain segments, introduced through the DA reaction, can effectively enhance the toughness of the epoxy resin. The chemical structure and properties of the materials were characterized by FTIR, DSC, TGA and universal testing machine. The results showed that due to the presence of soft polyurethane segment, improve the corrosion resistance and wear resistance of coating. Additionally, the Diels-Alder bond endowed the material with excellent thermal self-healing and recycling properties. Therefore, this modified epoxy coating shows great potential in extending service life of metal materials and bringing considerable economic and social benefit.