Thickness swelling and density variation in aspen flakeboards

Summary This paper reports the relationship between thickness swelling and density in labmade aspen flakeboards. The boards were manufactured with several levels of initial mat moisture content and urea resin content. Weight increase and thickness swelling at 12 locations on each board were recorded under specified environmental conditions over a period of 71 days. Each board was then cut into 12 specimens, each containing one of the 12 locations at its center, and density was calculated. No definite relationship was found between thickness swelling and density among the 12 specimens of each board. Our results suggest that high initial moisture content and high resin content can decrease thickness swelling. Variations in mat pressure and core temperature during the press cycle and weight increase at 80 percent relative humidity are discussed.The Forest Products Laboratory is maintained in cooperation with the University of Wisconsin. This article was written and prepared by U.S. Government employees on official time, and it is therefore in the public domain and not subject to copyright