EFFECT of HEAT TREATMENT on the SURFACE COLOR of RUBBER WOOD (HEVEA BRASILIENSIS)

Abstract

In this study the effect heat treatment process parameters (temperature, duration and heating rate) on the surface color of rubber wood was evaluated. The color of the rubber wood was determined using CIE L*a*b* system before and after the heat treatment. The colorimetric properties, including total color difference (∆E*), lightness index (L*), red-green index (a*), and yellow-blue index (b*), were investigated at different treatment conditions. The results of analysis of variance (ANOVA) indicate that the heat treatment temperature has a significant effect on the colorimetric properties of the heat-treated rubber wood, duration and heating rate has no effect. Within the experimental range, as the heat treatment temperature and duration increasing, the color of the rubber wood gradually deepens. In order to achieve a surface color like the teak wood, the optimum process conditions are heat treatment temperature 190°C, duration 4 h, heating rate 10°C.h-1