Effect of UV exposure on the surface chemistry of wood veneers treated with ionic liquids

In this paper, the influence of four types of imidazolium-based ionic liquids (ILs) on the chemical alteration of the surface of wood veneers exposed to 254 nm UV irradiation have been studied by using image analysis, Fourier transform infrared spectroscopy and surface energy calculation. The wood treated with ionic liquids showed better stability to UV light, as demonstrated by the low lignin, carbonyl index and cellulose crystallinity index variation, as well as very small color modification of the surface with the increase of the UV exposure period, by comparing to non-treated wood. The results show that the tested ionic liquids could be effective as UV stabilizers.

► Treating poplar wood veneers with four types of alkylimidazolium-based ionic liquids. ► Wood wettability is increased by ionic liquid treatment. ► Wood resistance to UV light exposure is increased by ionic liquid treatment. ► Decreasing the crystallinity and improving the flexibility of the cellulose matrix. ► Preservation of cellulose crystallinity at higher UV irradiation duration.