INVESTIGATION OF THE CHEMICAL CHANGES IN THE STRUCTURE OF WOOD THERMALLY MODIFIED WITH IN A NITROGEN ATMOSPEHERE AUTOCLAVE

Thermal modification beneficially alters several technological parameters of wood. The changes in the physical parameters are due to the significant/varaious alterations of the structure and the chemical composition of wood, which take place during the modification process. These changes arc complex and some aspects/processes are still far from being completely understood. What is known, is that by increasing the temperature the nature of reactions taking place changes. Still it is unknown the exact point where the individual reactions become dominant. Various industrially important hardwood and softwood have been treated in autoclave in N-2 atmosphere. The physical (density, L-value, moisture content, bending strength, MOE) and chemical (pH, hemicellulose-, totalphenol-, soluble carbohydrate-, and volatile organic compound content) parameters have been measured and evaluated. Correlations between physical and chemical parameters have been established and discussed.