Physico-mechanical Properties of Two Philippine Bamboos Thermally Modified in a Steam Environment

Abstract

Two commercial bamboo species – namely, “kauayan tinik” (Bambusa blumeana J.A. and J.H. Schultes) and giant bamboo [Dendrocalamus asper (Schultes et.) Backer ex Heyne] – were treated by thermal modification (TM) or heat treatment in a steam environment using temperature and duration settings of 175 °C – 30 min and 200 °C – 30 min. The effect of TM and the presence and absence of node on the physical and mechanical properties of bamboo were studied. Physical [moisture content (MC), thickness swelling (TSw), water absorption (WA), and specific gravity] and mechanical (flexural, compression, and tensile strength) properties were determined. A factorial experiment in a completely randomized design (CRD) was used to analyze the data. Results showed that TM improved the dimensional stability of bamboo as evidenced by lower MC, TSw, and WA compared to control samples. Except for tensile strength, the flexural and compressive strength of heat-treated bamboo did not significantly change at 175 °C – 30 min compared to the control. The presence of nodes, on the other hand, significantly reduced the bamboo samples’ flexural and tensile strength. Generally, TM improved the dimensional stability of bamboo without significantly affecting the mechanical properties at 175 °C – 30 min. At 200 °C – 30 min, a slight reduction in strength was observed, especially for D. asper.