Synthesis of tung oil-based vinyl ester resin and its application for anti-corrosion coatings

Anti-corrosion coatings are of great significance for marine equipment and engineering on account of the harsh marine environment. Vinyl ester resin is widely used as a resin material for anti-corrosion coating because of its excellent hardness and protective performance. However, the intrinsic brittleness of vinyl ester resin causes the resulting coating film with poor toughness. In this study, the tung oil-based toughen modifier (TOAMA) with a long carbon chain and annular structure is firstly prepared by Diels-Alder reaction of tung oleic acid and maleic anhydride under solvent-free conditions, and then used as a reactive toughening agent to synthesize toughened vinyl ester resin. The characterization results of Fourier transform infrared and hydrogen nuclear magnetic resonance spectroscopies reveal the successful synthesis of the TOAMA-toughened vinyl ester resin. Furthermore, the toughened vinyl ester resin is used in the anti-corrosion coatings, and the properties of the related cured coating films including thermostability, mechanical performance and corrosion resistance are systematically studied. The related results display that TOAMA can effectively toughen vinyl ester resin, and the toughened vinyl ester resin prepared with the optimized TOAMA content can effectively improve the mechanical properties including mechanical strength, elongation at break and fracture toughness, and achieve favorable thermal stability and excellent corrosion resistance of the cured coating films. Grafting tung oil-based toughening modifier TOAMA into the backbone of vinyl ester resin effectively provides a significant promising method to toughen vinyl ester resin, which is beneficial to the application of vinyl ester resin in the marine anti-corrosion coating field.