Synthesis and characterization of a novel UV-resistant epoxy based on vinyl ester/ZnO nanocomposite coatings

This research reports on the fabrication of a novel UV-resistant epoxy vinyl ester nanocomposite coating reinforced by ZnO nanoparticles to enhance the resistance of the coating against UV-induced degradation and improve long-term durability. The epoxy vinyl ester resin was synthesized by reacting of an industrial-grade epoxy resin with acrylic acid. For the preparation of UV-resistant coatings, ZnO nanoparticles were dispersed in the resin formulation at two different concentrations (0.1 wt% and 0.5 wt%) using a controlled dispersion technique, followed by curing under optimized conditions. The esterification process was carried out in the presence of triethylamine as a catalyst and hydroquinone as an inhibitor at 90–100 °C. The resulting resin was structurally characterized using Fourier transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and elemental mapping analysis. The results demonstrated that the incorporating of ZnO nanoparticles significantly improved the UV resistance, adhesion, and mechanical stability of the coatings. Pull-off adhesion tests (n = 2 replicates per sample) showed that the addition of 0.5 wt% ZnO nanoparticles enhanced the bonding strength from 4.91 MPa for the neat resin to 8.05 MPa, indicating a remarkable improvement in interfacial adhesion. Moreover, the contact angle test under UV exposure revealed that the 0.5 wt% ZnO nanocomposite maintained its hydrophobicity more effectively, showing minimal variation even after 20 days of UV irradiation. These findings indicate the potential of the developed nanocomposite coatings for protective applications and support the value of further long-term outdoor and accelerated weathering studies to confirm performance under harsher and more extended environmental conditions.