Manufacturing of Taiwania-Bamboo Charcoal Cement-Bonded Particleboard by carbon dioxide ejection Process

This study used thinned Taiwania (Taiwania cryptomerioides) wood and bamboo charcoal to prepare cement-bonded particleboard by rapid CO2 injection method. The effects of board forming conditions on the hydration temperature, physical, and strength properties of the board were investigated. Electromagnetic shielding characteristics of the boards, in particular, were compared. The results show that the hydration temperature of the mat increased with cement/material ratio and increasing carbon dioxide pressure. It also decreased with increasing bamboo charcoal content and the water/cement ratio. Hydration temperature showed dramatic decreases when water/cement ratio reached 0.50, the time to reach the highest temperature was notably prolonged, and the percentage of weight gain decreased. These showed that over water can inhibit the reaction between carbon dioxide and cement in the mat. Therefore, when we used hydration temperature curve and percentage of weight gains to determine the suitable manufacturing conditions, dimensionally stable boards could be formed in 4 min. Modulus of rupture (MOR) of the boards ranged between 24.42 and 43.15 kgf/cm2. When manufacturing variables were compared, the ratio of Taiwania to bamboo charcoal was the most important; it was followed by the cement/material ratio, and the manufacturing time had the least effect. The inserted electromagnetic loss value of the boards decreased with bamboo charcoal content and board thickness; while the reflective loss value showed an increasing tendency opposite that of the insert loss value. Therefore, we deemed that adding bamboo charcoal can enhance electromagnetic shielding characteristics of the boards