PRESERVATIVE TREATMENT OF BAMBOO CULM FOR PRODUCING GREEN COLOUR AND ENHANCING FUNGAL DURABILITY

This research was performed to investigate the feasibility of using copper-based wood preservative treatment for producing green colour on the bamboo surface and enhancing the fungal decay resistance of treated bamboo. Preliminary outdoor weathering tests were carried out to evaluate the green colour fastness of treated bamboo culms. In addition, fixation and leaching tests were also conducted to evaluate the safety of preservative-treated bamboo. A two-step treatment process was recommended to enhance bamboo green colour production, fungal decay resistance, production rate of treated bamboo and prevent sludge formation in treatment solution. In the treatment process, the bamboo was pressure-treated until refusal point with 4% chromated copper arsenate-3 to achieve required preservative retention and dipped into 4% chromated copper arsenate-3 for 2 days to produce green colour on the bamboo surface. The chromated copper arsenate-treated bamboo samples had outstanding colour fastness and mildew resistance after 24 months of outdoor weathering. The fixation and leaching tests demonstrated that the total amount of preservative components leached from the chromated copper arsenate-treated bamboo samples was high to raise safety issues and caused environmental problem during the use of treated bamboo in the field.