This work deals with the elaboration and the physical characterization of thermally modified wood with boiling palm oil. The heat treatment consists of dipping successively the wood into two baths of oil, the first one at a temperature about 200°C for 30 minutes and the second at ambient temperature of 23°C. This resulted in important color changes of treated specimens. The wood species used for the study are Sapelli and Ayous, two Cameroonian hardwoods. A compared study of the physical properties of treated and untreated wood was made. Hygroscopicity of heat‐treated wood has been tested. Samples were dipped in water and then kept in a room with a relative humidity of 65% and a temperature of 23 °C. The samples were periodically weighed over a period of 8 days. The conclusion was that during a short period the water permeability of heat‐treated Sapelli was 70 per cent lower than that of normal dried Sapelli. The same result was found for Ayous. Heat treatment significantly reduces the tangential and radial swelling. The Specific gravity of heat treated wood was almost constant, but higher than that untreated wood. After an adequate treatment, the moisture content of these woods after dipping in water for a long time was less than 7%. It is therefore possible for these treated woods to be used outside without biological attack due to moisture. In addition, the dimensions of treated wood were almost constant.
thermal modification of wood, hygroscopicity, swelling, water absorption, specific gravity, color.
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