Effect of thermal treatment on physicochemical properties of Gympie messmate wood

The aim of this study was to evaluate the chemical composition and the wettability of Gympie messmate (Eucalyptus cloeziana) thermally modified wood. To achieve this, Gympie messmate wood samples were thermally modified in an oven at 180–240 °C and in a combination of oven (180–240 °C) and autoclave (127 °C) for 4–5 h. Chemical composition were investigated by TAPPI standards, high-performance liquid chromatography, ATR-IR spectroscopy and thermogravimetric analysis (TGA), while wood wettability were evaluated by contact angle technique. The main results showed that increment of extractives was due to its condensation, while reduction most of the monomeric sugars was due to the thermal treatments at high temperatures. Hydrophobicity of thermally treated wood increased, in which treatments at 180 and 200 °C presented the best results in relation to the contact angle increment. The use of autoclave (pre-treatment) affects significantly only extractives and others sugars content. However, all the thermal treatments modified significantly the wettability and the chemical properties of Gympie messmate wood.

► Wettability and chemical properties of Gympie messmate wood were evaluated.
► The monomeric sugars in thermally modified wood decreased significantly.
► Thermal treatments affected chemical composition of wood.
► Thermal treatments at 180 and 200 °C presented the best results for contact angle
► Use of autoclave significantly affected only extractives and others sugars content.