Inhibition of the Photodiscoloration of Wood by Butyrylation

Abstract

Summary The lightfastness of butyrylated China fir (Cunninghamia lanceolata var. lanceolata) and maple (Acer sp.) was evaluated in this study, and its effectiveness was compared with that of acetylated specimens. The color fading in acetylated China fir and maple woods was reduced to half that of untreated specimens, after a 24-day UV lightfastness test. The effectiveness of butyrylation on photodiscoloration prevention in wood was even more pronounced than that with acetylation. With an 18.57% weight percent gain, butyrylation remarkably inhibited the discoloration of wood following UV irradiation. Based on infrared spectral analysis, the lignin of both untreated and butyrylated woods deteriorated after exposure to UV light, but the holocellulose in butyrylated wood was more resistant to the UV light. Furthermore, results obtained from diffuse reflectance UV-VIS spectral analysis elucidated that the absorption of irradiated butyrylated wood, in comparison with that of the irradiated but untreated specimens, was lower in both UV light and visible light regions. It also revealed that the inhibition of photodiscoloration of wood by butyrylation was caused mainly by a significant reduction of chromophoric derivatives, such as quinoid compounds, formed on the wood surface.