Facile construction of cardanol-based epoxy vinyl ester resin for UV-curable, tough, anticorrosive coatings

Epoxy vinyl ester resin (VER) has promising prospects in the anti-corrosion coatings application, due to their advantages including favorable chemical and corrosion resistance, remarkable mechanical strength and convenient processability. Nevertheless, traditional VER coatings are typically cured by time-consuming thermal treatment and exhibit poor toughness, making them inadequate for providing long-term corrosion protection to metals. In this study, cardanol-based epoxy vinyl ester resin (VER) was effectively constructed for obtaining UV-cured and tough VER coatings with long-term anticorrosive property. Herein, multifunctional cardanol-derived toughening modifier (CAMM) was firstly synthesized via thiol-ene click reaction between cardanol and 2-mercaptoethanol, followed by esterification reaction with maleic anhydride. Moreover, CAMM was grafted onto VER molecular to improve resin processability and coating film performances. Structural characterization confirmed the successful synthesis of CAMM and cardanol-based VER via Fourier transform infrared and hydrogen nuclear magnetic resonance spectroscopies. Rheological analysis indicated CAMM introduction effectively reduced VER viscosity. The optimized cardanol-derived VER coating film displayed the outstanding tensile strength of 76.53 MPa and toughness of 7.74 MJ m −3 , which were significantly higher than those of control VER sample with tensile strength of 57.44 MPa and toughness of 1.56 MJ m −3 . Additionally, the optimized coating film also exhibited the long-term anticorrosion performance with impedance modulus |Z| 0.01Hz of 6.42 × 10 9 Ω·cm 2 after 180-day immersion in 3.5 wt% NaCl aqueous solution, and perceptible antibacterial activities against Escherichia coli and Staphylococcus aureus . This work presents a promising approach to synthesizing multifunctional CAMM and high-performance UV-curable VER resins, which have great potential in the applications of anticorrosive coatings. • Multifunctional modifier (CAMM) is prepared via cardanol as raw material. • CAMM can exert dilution, toughening and antibacterial effects. • CAMM toughened epoxy vinyl resin (VER) film is formed by solvent-free UV-curing way. • CAMM-based VER film reveals excellent mechanical and anti-corrosive properties. • Toughened VER has promising application potential in anti-corrosion coating field.