Preparation of solvent-free epoxy resin coating and UV aging resistance evaluation

In view of the lack of systematic and scientific evaluation on the aging resistance of epoxy resin protective coatings for hydraulic concrete in high-cold and high-altitude regions, this study prepared a solvent-free CW epoxy coating. An ultraviolet-condensation accelerated aging test was conducted, combined with tensile tests, FTIR spectroscopy, DMA analysis, and microscopic morphological characterization, to investigate the aging mechanism and performance evolution of the coating. Furthermore, the thickness retention rate and the carbonyl peak area ratio were selected as failure indicators to establish a life-prediction model for analyzing UV aging resistance. The results show that the epoxy coating degraded during aging, exhibiting surface defects such as yellowing, powdering, and pinholes. In the early stage, the breaking of chemical bonds led to a decrease in tensile strength and glass-transition temperature (T_g). In the later stage, the cross-linking density increased, resulting in the recovery of tensile strength and T_g, while the area of the carbonyl characteristic peak also expanded significantly. The service life of the coating in Shigatse and Lhasa was approximately 49%~54% of that in Wuhan. These findings can provide a reference for performance optimization and engineering application of protective and repair materials for water-conservancy and hydropower projects in harsh and complex environments.