Einfluss der hydrothermischen Behandlung von Picea abies (L.) Karsten und Eucalyptus nitens(Deane & Maiden) Maiden auf die chemische Zusammensetzung des Holzes | Influence of hydrothermal treatment on the chemical composition of Picea abies (L.)Karste

Wood of Picea abies and Eucalyptus nitens was heated for 60 minutes in an autoclave with overheated water vapour at temperatures of 140 °C to 170 °C. Pressure in the autoclave rose with increasing temperature. The chemical composition of the wood was ascertained according to the treatment (relative chemical composition, proportion of extractable substances and pH-value). With increasing temperature the pH-value fell while the proportion of substance extractable in hot water rose. The loss of pentosan due to temperature raise was higher for Picea abies than for Eucalyptus nitens. Meanwhile, the increment of soluble constituents in toluene, in warm water and in 1% NaOH solution was higher for Eucalyptus nitensthan for Picea abies. The proportion of extractable substances increased strongly at temperatures above 140 °C. The equilibrium moisture content and the swelling due to vapour adsorption hardly varied for either species.