Effects of boron Impregnation and heat treatment on some physical and mechanical properties of spruce and pine wood

Abstract

This study evaluated the effects of boron impregnation and heat treatment on some physical and mechanical properties of wood. Spruce and pine wood samples were treated with 4% aqueous solution of both boric acid (BA) and borax(BX) by using full cell method, and then were exposed to heat treatment at 212 ºC for 120 min in an industrial site system. After the treatments, the physical (water absorption and tangential swelling) and mechanical (bending and compression strengths) properties of the specimens were measured according to the related standards. In addition, the remained boron content in heat treated wood specimens was analyzed by means of Inductively Coupled Plasma (ICP). There were generally negative changes in mechanical properties of heat treated wood due to boron treatment. Boron treatment significantly increased water absorption and decreased tangential swelling values of heat treated wood. It appears that heat treatment provide boron retention of about 18-63 % of initial amount depending on boron compound and wood species.