FLATTENING OF HALF TUBULAR BAMBOO CULMS AND FIXATION OF BAMBOO BOARDS

Abstract

PARKKEEREE T,MATANN,MATANN&KYOKONGB. 2014. Flattening of half tubular bamboo culms and fixation of bamboo boards. The objective of this work was to maximise the utilisation of bamboo (Dendrocalamus asper) by overcoming constraints due to its tubular formin producing flat bamboo board.Watersaturated half tubular bamboo specimens (thickness of 3mmand length of 150 mm) were pressed under various loads (10 to 25 N) while being immersed in hot linseed oil at different temperatures (120 to 180 °C). The height of each specimen was measured as a function of time. The flattened bamboo boards were hot pressed at 0.65 MPa at temperatures between 180 and 240 °C for up till 40 min. Springback of fixed bamboo boards in ambient air (28 °C and 75% relative humidity) and in water was assessed. The half tubular bamboo culms were best flattened in hot linseed oil under applied load of 15 N and 160 °C. Without an additional fixation at high temperature, final springback levels of 52% in ambient air and 73% in water were observed. These springback levels were reduced to below 5% in ambient air and 40% in water by hot pressing the flattened bamboo boards
at 240 °C for at least 20 min. After fixation, the colour change of bamboo specimens was a good indicator of the springback observed.