Characterization of heat treated wood species

The objective of this work is to investigate the effect of heat treatment on swelling, hardness and surface quality of samples from four species, namely mindi (Melia azedarch L.), mahogany (Swietenia macrophyla), red oak (Quercus falcate Michx.) and Southern pine (Pinus taeda L.). Specimens were exposed to temperature levels of 130 °C and 200 °C for 2 and 8 h. Swelling values of the control and heat treated samples were evaluated by soaking them in water for 2 h. Surface quality and hardness of the species were also determined using a stylus technique and Janka hardness, respectively. Based on the findings in this study dimensional stability of all four types of samples improved with heat treatment. Surface quality of the specimens was also significantly enhanced by exposing them to heat. Micrographs taken from scanning electron microscope revealed that there was some distortion and modification of the cells due to heat treatment. Overall hardness of the samples was adversely influenced by heat treatment. It seems that properties of the species evaluated in this investigation were more pronounced with increasing temperature and time span.