Canadian Journal of Chemical Engineering, Vol.93, No.1, 29-36, 2015
SUPERFICIAL SOLVOTHERMAL TREATMENT OF THE LIGNOCELLULOSIC BIOMASS IN IONIC LIQUIDS - HYGROSCOPICITY, MORPHOLOGY AND MECHANICAL PROPERTIES
Surface heat treatment of wood improves its hydrophobic, antifungal, and anti-swelling properties, and strengthens its resistance to the vagaries of natural exposure. We investigated the relevance of a superficial solvothermal treatment of wood specimens impregnated with hydrophilic ([EMIM][OTf]) and hydrophobic ([EMIM][OTf]) ionic liquids which we compared to a conventional heat treatment under nitrogen atmosphere over the following treatment temperature and time ranges: [180 degrees C - 260 degrees C] and [30min - 4h]. The treated specimens were subjected to moisture adsorption, water absorption, swelling, and mechanical properties testing. The results revealed a notable decrease in ultimate moisture content and water uptake of the samples, provided they were impregnated with a hydrophobic ionic liquid before heat treatment at temperatures less than 200 degrees C. However, the mechanical properties testing showed that the elastic and rupture moduli of specimens decreased with increasing treatment temperature and time irrespective of using ionic liquids. However, the impregnated samples suffered in general increased breakability which was ascribed to partial solubilization of wood components in the ionic liquid.