Comparative Study on UV Degradation of Black Chinese Lacquers with Different Additives

This study investigates the UV degradation of black Chinese lacquer by incorporating carbon black and ferrous hydroxide as additives. The purpose of this research is to understand the effects of these additives on the degradation behavior of the lacquer film. Different concentrations of carbon black powder (1%, 3%, and 5%) and Fe(OH)₂ (10%, 20%, and 30%) were added to the lacquer following traditional techniques. The main methods employed for analysis were gloss loss measurement, color change assessment, SEM imaging, FTIR spectroscopy, and XPS analysis. The results demonstrate a significant decrease in gloss levels and an increase in lightness values with increasing ultraviolet exposure time. SEM images reveal the formation of cracks in the lacquer film. FTIR analysis indicates oxidation of the urushiol side chain and an increase in oxidation products. The infrared difference spectrum highlights the differences between the additives, with Fe(OH)₂ showing a lower impact on the spectra compared to carbon black. XPS analysis confirms the oxidation of the C-H functional group and the presence of C-O-C and C-OH groups. In conclusion, this study sheds light on the influence of carbon black and ferrous hydroxide additives on the UV degradation of black Chinese lacquer and suggests the protective effect of Fe(OH)₂ against UV aging. These findings contribute to a better understanding of the degradation mechanisms and provide insights for improving the UV resistance of Chinese lacquer coatings. Further research can explore alternative additives and optimization strategies to mitigate UV-induced degradation.