The color of wood is a critical factor in determining its aesthetic appeal and commercial value. However, extended exposure to light has been shown to induce a range of undesirable effects, including gloss loss, color deterioration, and an increase in surface roughness. These effects can limit the application of the material in high-end contexts. In order to develop an eco-friendly strategy for enhancing the photostability of dyed wood, this study fabricated Russian oak (Xylosma Racemosum) veneers colored with complexes formed between tannic acid (TA) and metal ions (Fe²⁺, Mn²⁺, Cu²⁺). The color fastness to water and ultraviolet (UV) light was comprehensively assessed. The dyed veneers demonstrated superior water resistance, exhibiting a negligible color difference (ΔE* < 2) after immersion. However, they showed inadequate UV light fastness, undergoing substantial color fading (ΔE* up to 4.10) after 288 h of aging. The characterization results indicated that the UV-induced fading was accompanied by severe surface roughening and micro-cracking (SEM observation). In addition, the degradation of lignin's aromatic structure and the formation of hydrophilic oxygenated groups were evident through FTIR analysis. The application of a 5% color-fixing agent (UV-1130) significantly enhanced the photostability, reducing the ΔE* value by 41%, 63%, and 53% for the TA-Fe²⁺, TA-Mn²⁺, and TA-Cu²⁺ systems, respectively. The microstructural analysis confirmed that the color-fixing agent contributed to preserving surface integrity following UV exposure. This work provides a viable and sustainable approach to achieving durable coloration for wood veneers by combining green TA-metal complex dyeing with an effective protective post-treatment. • Novel eco-friendly dyeing of oak veneer via tannic acid-metal complexation. • Color fastness to water and UV light of dyed veneer is systematically evaluated. • Analysis of wood interface coordination structures reveals color stabilization mechanisms. • Enhances weather resistance for exterior and architectural uses. • Achieves deep dyeing and protective treatment in one efficient process.
Qi et al. (Thu,) studied this question.