Improving the UV degradation resistance of epoxy coatings using modified carbon black nanoparticles

•Degradation behavior of modified carbon black (CB) epoxy coating was studied under condition of UV irradiation.•By using SDS as a surfactant, nanoparticles of CB were uniformly dispersed in an epoxy matrix.•ATR-FTIR analysis showed that the coating with 2.5wt% CB nanoparticles was degraded less than epoxy coating.•Adding 2.5wt% CB into the coating exhibited no microcracks with a less degree of discoloration than the neat epoxy coating. Degradation mechanisms of modified nano carbon black (CB)-epoxy coatings were investigated under condition of UV irradiation. Transmission Electron Microscopy (TEM) and Field Emission Scanning Electron Microscopy (FESEM) confirmed that nanoparticles were finely distributed throughout epoxy resin and its solvent. Various characterization tools, including ATR-FTIR, colorimeter and Optical Microscope (OM) were used to evaluate the effects of CB content on the progressive changes in chemical elements, color and microcracks of the nanocomposite coatings. ATR-FTIR analysis indicated that concentration of carbonyl group generated by chain scission was much less for the 2.5wt% CB nanocoating than the neat epoxy coating. It was found that microcracks were appeared on the neat epoxy coatings surfaces after 1000h UV exposure. No microcracks were observed in 2.5wt% CB nanocoating. It was revealed that CB nanoparticles were good UV stabilizers that could absorb UV irradiation and protect epoxy-based coatings.