Effect of lignin and hemicelluloses removal on dynamic water vapour sorption behavior of wood

• Water-related properties of wood are strongly depended on the sorption behavior of its hygroscopic polymers such as cellulose, hemicelluloses and lignin. To assess the sorption performance of wood matrix in the absence of hemicelluloses and lignin, micro-veneers of Scots pine (Pinus sylvestris L.) were hydrolyzed with sulphuric acid and delignified with sodium chlorite and acetic acid, respectively. The dynamic water vapour sorption of the hydrolyzed, delignified and untreated veneers was studied in a dynamic vapour sorption (DVS) apparatus. The moisture adsorption of hydrolyzed veneers was decreased in the relative humidity (RH) range above 60-70 %. Delignified veneers, however, showed obviously higher moisture adsorption at RH above 70%, as compared to untreated controls. Hydrolyzed and untreated veneers exhibited a comparable hysteresis, while delignified veneers showed a considerably lower hysteresis in comparison to them. This explains that, despite the fact that the hydrophilic hemicelluloses influence the moisture sorption of wood, the expand-ability of the cell wall matrix is mainly controlled by lignin.

Ämnesord

LANTBRUKSVETENSKAPER  -- Lantbruksvetenskap, skogsbruk och fiske -- Trävetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Wood Science (hsv//eng)

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