Abstract
Blue-stained wood cut from bark beetle-attacked southern pine has a lower economic value than unstained wood. Wood composite products containing blue-stained wood may offer an opportunity to recover some lost timber value. This study investigated the surface-free energy of blue-stained wood. Southern pine sapwood samples with and without blue stain from both green and kiln-dried sources were obtained. Dynamic contact angle analyses were performed using three probe liquids: ethylene glycol, formamide, and deionized water. Surface-free energy was determined by applying the geometric mean model using two-liquid pairs with deionized water. The polar forces were higher across all wood types and in water–ethylene glycol vs water formamide. Surface-free energy of air-dried blue-stained sapwood was lower than all other wood types. However, kiln-dried blue-stained sapwood had a higher surface-free energy than all other wood types. These results were indicative of a tree’s wound response to bark beetle attack, the volatilization of naturally occurring hydrocarbons in southern pine sapwood, and the resulting increase in wood permeability caused by blue-stained fungal colonization across the sapwood. However, improvements in wetting observed for kiln-dried blue-stained sapwood may lead to cost and quality issues in wood composite manufacturing associated with over drying and overpenetration of an adhesive.
Keywords
Blue-stain, bark beetle, dynamic contact angle, southern pine, surface-free energy, wood composite.
To read the full article please visit the link below:
Little, Nathan S., T. Eric McConnell, Nathan E. Irby, Sheldon Q. Shi, and John J. Riggins. 2013. “SURFACE FREE ENERGY OF BLUE-STAINED SOUTHERN PINE SAPWOOD FROM BARK BEETLE-ATTACKED TREES.” Wood and Fiber Science 45 (2): 206–14.