Changes in Colour, Strength and Chemical Properties of Oil Heat Treated 18-Years Old Planted Acacia mangium

Abstract

This study was carried to investigate changes in the oil heat treated 18-years old of planted Acacia mangium. Harvested trees segregated into bottom, middle and top portions containing heartwood and sapwood were oil heat treated in stainless tank with palm crude oil as heating medium at temperatures of 180oC, 200oC and 220oC for 30, 60 and 90 minutes respectively. The evaluation of the changes in the wood were performed by standards using a Minolta Chroma Meter, TAPPI Standard T204 om-88, TAPPI Standard T203 cm-99, TAPPI Standard T222 cm-02, and BS EN 310:1993 static bending tests. The relationship between the changes in the colour, mechanical and chemical composition, were made using correlation analysis. The result showed oil-heat treatment reduced the lightness of the wood and darkened the both parts of the wood. The strength of the wood reduced slightly after the oil-heat treatment. In the chemical compositions, the percentages of the holocellulose, α-cellulose, hemicellulose and extractive contents decrease with the increase in treatment duration and temperature. The oil heat treatment process at 200°C for duration 60 minutes is recommended for acacia mangium wood as it improved the colour of Acacia mangium and standardized the colour of sapwood and heartwood. The loss in strength at this temperature and duration is acceptable as the treated wood only loss up to 15% strength in MOR and 10.7% in MOE.