Comparisons of the photostability of esterified wood

The light stability of wood panel treated with acetic anhydride, succinic a nhydride, maleic anhydride, and phthalic anhydride was compared. Results fr om the solid state CP/MAS C-13 NMR analyses revealed that the esterificatio n of holocelluloses occurred mainly at the C-6 position in the amorphous ce llulose component. After lightfastness testing, the change in the color of wood treated with phthalic anhydride was greater than that subject to the o ther treatments. The color difference and yellowness index of acetylated wo od after irradiation were significantly less than controls, indicating that acetylation inhibited the photoyellowing of wood. In addition, results obt ained from diffuse reflectance UV-VIS spectral analyses clearly demonstrate d that the amount of chromophores generated in wood treated with phthalic a nhydride was more than that of the untreated control after photodegradation , and that the amount of chromophores on the irradiated acetylated wood sur faces was much less than that of the others. Acetylation reduced the format ion of colored derivatives on the wood surfaces and consequently inhibited the photodiscoloration of wood. (C) 2001 Elsevier Science Ltd. All rights r eserved.