Effect of highly efficient steam explosion treatment on beech, poplar and spruce solid wood physicochemical and permeable performances

The effect of steam explosion treatment (SE) on the appearance and water permeability of solid beech, poplar, and spruce wood was investigated. Wooden test specimens were steam blasted after water or acid impregnation at 10 ~ 16 bar for 5 ~ 15 min, and their chemical composition was determined by chromatographic analysis after hydrolysis and infrared spectroscopy. Macro/micro cracks with shrinkage and reduced sphericity after drying were observed by scanning electron microscopy. Darker color and more severe changes in colorimetric parameters were measured spectrophotometrically for SE treated samples, especially under acidic conditions or higher severity factors (SF). To some extent, the physicochemical and permeability properties of SE treated wood samples could be simulated by considering the correlations of the different factors. No significant deterioration in chemical content, longitudinal compressive modulus of elasticity (MOE//) and modulus of rupture (MOR//) was observed in SE specimens treated with water. Higher permeability was obtained under a mild condition of 180 °C-5 min for poplar and a higher SF condition for beech and spruce. Therefore, SE could be an efficient method for modifying solid wood to improve its permeability and functionality.