Lignin grafted pyridinized graphene oxide based self-healing anti-corrosion composite coating

The use of biomass material to modify nanomaterials is an effective way to enhance the anti-corrosion properties of coatings. In this work, modify graphene oxide (GO) and pyridinized graphene oxide (TGO) using lignin through D-A reaction, and then combined with resin to prepare a composite coating with excellent anti-corrosion properties under thermal polymerization. The results showed that after being soaked in salt water for 120 days, the impedance modulus of the lignin grafted TGO-based composite coating was two orders of magnitude higher than that of the control group, and its anti-corrosion performance was superior to that of the lignin grafted GO-based composite coating. Molecular dynamics simulations showed that the presence of pyridine groups promoted the directional arrangement of GO, with an orientation angle of 10°. This made the diffusion path of the corrosive medium in the coating more tortuous, thereby prolonging the service life of the metal. Scratch experiments showed that lignin grafted TGO-based composite coating had fewer corrosion products at the scratch site and exhibited excellent self-healing anti-corrosion properties. This work not only provided a new preparation method for modifying nanomaterials with lignin, but also offered a reference for the design of sustainable self-healing anti-corrosion coatings.