Abstract
As a recycling method of wood wastes, a carbonization process under high pressure of 4MPa and temperature of 523-623 K with treating time of 10-30min. was developed to produce a board without using any organic adhesives or solvents. The carbonization behavior during operation was analyzed and the properties of carbonized board as construction materials was evaluated using the particles of Japan cedar. The carbonization proceeded much at the periphery of board surface compared with inner part, although the strength of the board was satisfactory at all points of the board. It was also shown that simultaneous thermal and mechanical treatments were essential to obtain high strength. Only thermal or mechanical treatment yielded very weak board. These findings supported the speculation that lignin extruded at high temperature played the role of an adhesive to join the wood particles under high pressure. This assumption was examined by TG/DTA measurements of the board. The quality of the carbonized board was evaluated by mechanical strength, sound absorbing characteristics and heat transfer characteristics. The carbonized board was inferior to commercial particleboard in mechanical strength, but was superior in sound absorbing and heat insulation performance.
