INFLUENCE OF WOOD EXTRACTIVES ON MOISTURE SORPTION AND WETTABILITY OF RED OAK (QUERCUS RUBRA), BLACK CHERRY (PRUNUS SEROTINA), AND RED PINE (PINUS RESINOSA)

摘要

Red oak (Quercus rubra), black cherry (Primus serotina), and red pine (Pinus resinosa) wood samples were soxhlet extracted with various combinations of organic solvents including ethanol, toluene, and water according to ASTM 1110-96, ASTM Dl107-96, TAPPI T207 OM-88 and TAPPI T204 om-88 standards. Contact angle and sorption isotherms of extracted and unextracted specimens were determined to evaluate the role of wood extractives on the wettability and sorption properties of these wood species. Extracted specimens adsorbed more water than unextracted specimens at high relative humidity in agreement with the literature. The contact angle decreased with increased extraction due to the removal of hydrophobic extractives. However, the absorption rate of water, estimated as the decrease in contact angle over time suggests physical modification of the wood surface by solvent extraction due to the migration and redistribution of hydrophobic extractives.