Aging performance of nano‐Zno modified polyurethane‐acrylic UV ink composites on wood and the degradation mechanism

Nano‐ZnO was applied to modify the yellow polyurethane‐acrylic UV ink by physically blending and then the modified ink composites were used for wood printing. The color and gloss of the printed samples before and after aging were tested at periods. The aging mechanism of the ink composites was investigated was analyzed by XPS and FTIR analyses, and the morphologies were observed by AFM analysis. The results showed that the UV ink composite underwent oxidation during aging. Cromatism and gloss changed, and bulges existed on the surface in both untreated and nano‐ZnO modified samples. However, the situation of the nano‐ZnO modified UV ink composite printed samples after aging test was not as server as that printed with the unmodified one. During light aging, the primary amine, CO ₂ , and carboxylic acid were yielded, and NH radicals were generated, which promoted the formation of conjugated structure and the chromogenic enamine. As expected, these reactions were inhibited by adding of nano‐ZnO. Consequently, the light‐resistant of the UV ink composite was improved. 1.0% nano‐ZnO offered the lowest chromatism and the gloss changes among all, showing the best light‐resistant performance. POLYM. COMPOS., 40:3533–3540, 2019. © 2019 Society of Plastics Engineers