SWELLING AND TRANSVERSE ANISOTROPY OF IMPREGNATED AND COATED SPRUCE WOOD (Picea abies Karst)

Abstract

The impregnation is a capillary filling of cells, a method of modification whereby other viscous materials can also be introduced into the wood. Through the method of double vacuum impregnation, spruce wood pieces (Picea abies Karst) were treated by using polyurethane and acrylic wood coatings. In addition, identical test pieces were surface treated with the same coatings. This paper includes a comparison of the weight percent gain (WPG) caused by impregnation and by surface coating of the wood. The impact of impregnation and surface coating on the swelling and the transverse anisotropy were also studied. The swelling of the impregnated wood occurs in the first 2 to 3 days, after which it is stagnating. The swelling of the coated wood continuously increases in a period of seven days and it tends to keep increasing. The swelling of the impregnated wood and the coated wood is equalised on the fourth day of immersion of the wood samples. After the seven-day period of immersion, the coated wood shows greater swelling than the impregnated wood and is equated with the untreated wood. There are no significant changes in the anisotropy of the untreated, the impregnated and the coated spruce wood.