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Abstract

The aim of this work is to investigate the effect of heat treatment on swelling properties, hardness, physical appearance, morphological changes and flexure behavior of three timber species called Oak (Tabebuia rosea), Teak (Tectona Grandis) and Chanul (Humiriastrum procerum). Samples were exposed to different temperature levels of 130°C, 150°C , 180°C and 210°C for periods of 2, 4 and 8 hours. The swelling values and moisture absorption of the control specimens and the thermally treated samples were evaluated after water immersion at 2 and 24 hours. The surface quality and appearance of the wood pieces were compared between the treated samples and those that served as reference, and thus some differences in color change, porosity and shape were found. The species hardness was determined according to the Janka ball hardness method in the three sectional planes. Based on literature, the present study intended to demonstrate that the dimensional stability of the three proposed timber species would be improved by heat treatment.

Macroscopic analysis through stereoscopy was used to determine certain characteristics of the wood cell wall, and possible distortions and modifications related to the heat treatment conditions. Flexural strength was analyzed to determine mechanical properties in wood such as the stress in the proportional limit (ELP), flexural modulus of elasticity (MOE), modulus of rupture (MOR), and

to further correlate these with the different heat treatment conditions.