Zinc doped epoxidized lignin/graphene oxide anti-corrosion composite coatings with self-healing and UV resistance properties.

The advancement of bio-based intelligent anti-corrosion coatings represents an inevitable direction in sustainable materials science. In this study, releasable zinc ions were loaded onto epoxidized lignin with graphene oxide (GO) ring opening to prepare functional biomass nanofiller (LGO@Zn). Subsequently, a composite coating with both self-healing and anti-corrosion properties was prepared by compounding LGO@Zn with vinyl ester resin (VER). The results showed that LGO@Zn had good dispersion and interfacial interaction in VER. The composite coating showed exceptional UV-shielding performance and thermal resistance. The electrochemical test showed that LGO@Zn could significantly enhance coating corrosion resistance. Even if the coatings were soaked in 3.5 wt% saline solution for 100 days, the impedance modulus of the coating with 0.2 wt% LGO@Zn (1.44 × 1010 Ω·cm2) was 2.5 orders of magnitude higher than that of the pure resin coating (7.5 × 107 Ω·cm2). Scratch test showed that adding LGO@Zn endowed the coating with self-healing performance. The scratch coating adding 0.2 wt% of LGO@Zn exhibited optimal performance, exhibiting an impedance modulus one order of magnitude higher than that of pure resin. In summary, this work provided a novel design strategy for the preparation of self-healing anti-corrosion coatings, while promoting the application of biomass material lignin in sustainable coatings.