The sorption behaviour of wood is affected clearly by thermal modification processes. Depending on modification temperature and -duration the equilibrium moisture content (EMC) is reduced by up to 50%.
The aim of the investigations was to evaluate the influence of a thermal treatment on the kinetics of the water vapour sorption of spruce (Picea abies (L.) Karst.). In addition the unsteady-state sorption process between two equilibria of humidity was modelled as a diffusion process. After recording the rate of sorption of wood samples using the gravimetric method a water vapour diffusion coefficient of the material could be determined through inverse parameter identification.
The experimental rig for continuous plot of unsteady water absorption permits a simultaneous examination of two wood samples under identical test conditions.
The comparability and repeatability were examined first on twin samples of spruce. Subsequently, comparative investigations on natural and modified twin samples were accomplished.