A new system for enhancing the penetration of liquid into wood using a precompression treatment was designed, and the effects of compressive deformation and recovery on liquid uptake were evaluated. Precompression of up to 60% under appropriate moisture and heat conditions effectively increased the penetration of liquid into refractory wood samples of practical sizes without producing any strength reduction. Water-saturated wood was compressed perpendicularly to the grain at temperature of 30 to 80°C, and two types of pretreated wood were prepared; i.e., set-recovered wood in which loading was released immediately after precompression, and preset-fixed wood which was dried under the influence of a decompressive force. The amount of liquid taken up by set-recovered wood was 2-3 times that taken up by untreated wood. When preset-fixed wood was dipped in liquid and the deforming force was released, liquid penetration was more than 25 times that seen in untreated softwood heartwood. Liquid effectively penetrated even long samples when pressure impregnation was applied to precompressed and preset-fixed wood. No significant reduction of strength was observed for treated wood except for that which had been precompressed up to 60%. Fracture of pit membranes during compression with little damage to unpitted cell-walls and an elastic recovery process were believed to improve liquid penetration with negligible compression defects.

Download document (676 kb)
free for the members of IRG. Available if purchased.

Purchase this document