Preparation of a Vanillin-Based Active Ester Curing Agent and the Low Dielectric, Antibacterial, and Anticorrosion Properties of Its Coatings

At present, the dielectric constant of anticorrosion coatings is relatively high, which limits its application in electronic devices, and the epoxy curing agent currently used is mostly from fossil resources, which is not conducive to sustainable development. Therefore, a vanillin-based active ester curing agent (VAEI) containing an imine bond was prepared by the esterification reaction and amine aldehyde condensation reaction. Subsequently, VAEI and amino curing agents cured the epoxy resin to prepare a coating with antibacterial properties, low dielectric, and corrosion resistance. The results showed that when the content of VAEI was 5 wt %, its anticorrosion properties were basically equivalent to that of the coating prepared by the pure amino curing agent. When the content of VAEI was 14 wt %, the impedance modulus of the coating was as high as 1.00 × 10⁹ Ω cm² after soaking in salt water for 150 days, which was 2 orders of magnitude higher than that of the control group. In addition, the dielectric constant of the coating at 10 MHz decreased from 4.16 to 3.64, and it also exhibited excellent antibacterial properties against Escherichia coli (7.0%) and Staphylococcus aureus (19.6%). This work expands the added value of vanillin and provides a reference for the preparation of various performance coatings.