earticle

영어

Gmelina (Gmelina arborea) and mindi (Melia azedarach) are promising fast-growing woods species that is widely planted in community forests and industrial plantation forests in Indonesia. However, owing to its low strength, dimensional instability, and low durability, the use of the woods is restricted to interior applications only. Improvement in dimensional stability dan durability of gmelina dan mindi woods can be achieved by heat treatment which has long been recognized as an effective method to enhance the stability of wood. The objective of this study was to improve color properties and dimensional stability of gmelina and mindi woods via oil heat-treatment. The wood specimens were heat-treated at 180°C, 200°C, 220°C, and 240°C in palm oil for 1 h, with a heating rate of 2°C/min. The effect of temperature during heat-treatment on the color change and dimensional stability was evaluated. The color change was determined using the CIE-Lab color system and dimensional stability was evaluated through the measurement of equilibrium moisture content and water absorption. The results showed that the color of heat-treated woods became more uniform and darker by increasing treatment temperature. The overall color change (ΔE*) in both wood species most affected by the reduction in lightness (L*) and yellow/blue chromaticity (b*) by heat treatment. ΔE* increased with increasing treatment temperature with a higher degree obtained in gmelina compared to mindi wood. Dimensional stability of gmelina and mindi improved by heat treatment, as suggested by a lower equilibrium moisture content and water absorption compared to untreated samples. Furthermore, heat-treated mindi absorbed less water than gmelina. The results suggested that oil heat-treatment could enhance the color properties and dimensional stability of gmelina and mindi woods for value-added products.