LAUSR

This study has focused on solute diffusing into cell walls in solution-impregnated wood under conditioning, process of evaporating solvent. The amount of the diffusion is known to be determined by the solute diffusivity and the solute-concentration difference between cell walls and cell cavities. Purpose of this paper was to clarify the effect of temperature only on the solute diffusivity that is directionally related to the thermal vibration of the solute molecule. The cross-cut block of hinoki (Chamaecyparis obtusa), polyethylene glycol (PEG1540), and water was employed as wood sample, solute, and solvent, respectively. The sample impregnated with a 20 mass% solution was conditioned at 20, 35, or 50 °C to finish the solute diffusion evaluated using the dimension of the sample that was conditioned followed by drying in a vacuum. To unify the solute-concentration difference, for all temperatures, the equilibrium moisture content was unified and the solvent-evaporation rate was controlled in three ways during conditioning. The solute diffusivity was higher in order of 35, 50, and 20 °C, which was evaluated by the solute diffusion at the same evaporation rate. It is clarified that the diffusivity increases with increasing the dimension of cell walls rather than with increasing the thermal vibration of solute molecule.