Effects of hot water extraction on physical and chemical characteristics of oriented strand board (OSB) wood flakes

Research has already shown that extraction of valuable hemicellulose-rich streams is a viable option for revenue generation in the pulp and paper industries. Applying this value prior to pulping concept to the composite panel industry is a natural extension. If an extraction of hemicellulose is accomplished under the right conditions, a non-trivial amount of chemicals can be generated while leaving the woody substrate structurally intact for production to traditional products, such as oriented strand board (OSB). This research studied the effects of hemicellulose removal by hot water extraction on softwood OSB wood flakes and focused on changes that occurred in the physical and chemical properties of the wood flakes and liquid hydrolysates during extraction. Three reaction temperatures (120, 140, 160 degrees C) and three isothermal hold times (20, 40, 60 min) were investigated. Results indicated that the extraction of hemicellulose in quantifiable levels begins at 120 degrees C and 40 min and cellulose extraction begins at 140 degrees C, 40 min. The level of extraction of lignocellulosic materials, the decrease of wood flake thickness, and the acidity of the recovered hydrolysates all increase with increases in extraction severity. The most promising results in regards to industrial implementation of hemicellulose extraction occur at a temperature of 140 degrees C.