Temperature dependence of thermal conductivity of heat-treated rubberwood

This paper aimed to investigate the temperature dependence of thermal conductivity of heat-treated rubberwood (HTR). Rubberwood specimens were thermally treated at 180 degrees C with three different durations of 15, 25 and 35 h, respectively. Thermal conductivity values of HTR at various mean temperature ranges were then examined. That of untreated rubberwood (UTR) was also measured as a comparison. The result showed that thermal conductivity of UTR and HTR increased with increasing temperature for all durations as a linear relationship in which the values of HTR were lower at all examined temperatures. The rate of change of thermal conductivity with temperature of HTR for durations of 15 and 25 h and UTR was similar (similar to 0.0004 W/mK/degrees C). However, rubberwood heat treated for 35 h was much less sensitive to temperature compared with the UTR, showing a relatively small change of thermal conductivity with temperature (similar to 0.0001 W/mK/degrees C), which is comparable to typical insulation materials. This indicates that heat treatment could improve the thermal stability of rubberwood subjected to varying temperatures. In view of environmental and energy concerns, HTR should therefore be considered as one of the best potential raw materials for energy efficient building construction.