Chemical changes of beech wood due to CO2 laser irradiation

The paper deals with color changes and wood component changes caused by laser beam irradiation. A 500 mm × 150 mm × 15 mm beech (Fagus sylvatica, L.) board was irradiated by the CO2 laser beam at different exposures (expressed as the irradiation dose). The color changes were measured by the spectrophotometer and described in the CIELAB color system. Changes in the main wood components were observed by the Fourier transform infrared spectroscopy (FTIR) and carbohydrates were analysed by the gas chromatography of their aldonitrilacetates. With increasing the irradiation dose (from 14 to 57 J cm−1) was observed a continual growth of the total color difference (ΔE*). Predominantly hemicelluloses degradation was observed, while at a higher energy dosage lignin condensation occurred.

► We examine influence of CO2 laser on beech wood.
► We examine color and structural changes of lignin and polysaccharides.
► With increasing the irradiation dose an increase of the total color difference was observed.
► Predominantly hemicelluloses degradation was observed, lignin is more stable biopolymer.
► CO2 laser irradiation can be used as a new coloring method.