WOOD RESEARCH Volume 69, Number 1, 2024
QUANJI LU, HUICHUAN JIANG, JIANING LI, MIN LI, and GUANJUN LI

SOME PHYSICAL AND MECHANICAL PROPERTIES OF COCONUT PALM (COCOS NUCIFERA) STEM IN HAINAN ISLAND, CHINA

The physical and mechanical properties of 40-year-old coconut stem were investigated in different radial directions and height positions. The results showed that in the radial direction, the properties of the number of vascular bundles (NVB), density, shrinkage, compressive strength parallel to the grain (CS), modulus of rupture (MOR), and modulus of elasticity (MOE) decreased continuously from the outer area to the inner area, except for the water absorption (WA) value which increased from the outer area to the inner area. The density and MOE decreased from the bottom to the top in the height direction while NVB and WA increased. The shrinkage, CS, and MOE first increased and then decreased from the bottom to the top. NVB in coconut stem affects the density and determines the main mechanical properties of CS, MOR, and MOE. The analysis of variance (two-way ANOVA) showed a significant difference in density, NVB, WA, CS, MOR, and MOE in radial direction and height position. These findings can be useful for the development of new applications for coconut stems, such as in construction, landscaping, or furniture manufacturing, as well as for improving our understanding of their structural characteristics

WOOD RESEARCH Volume 67, Number 3, 2022
CUIXIANG LU, YUAN LIU, HUICHUAN JIANG, and QUANJI LU

Impact of heat treatment on the surface color and glossiness of young eucalyptus wood

The study analyzed the impact of heat treatment conditions (temperature and duration) on the surface color and glossiness of young eucalyptus wood. The young eucalyptus wood samples were treated at different treatment temperatures (165°C, 185°C, 205°C) and duration (2 h, 3 h, 4 h). The color of the young eucalyptus wood was determined using CIE L*a*b* system and the gloss was measured with glossmeter at 20°, 60°, and 85° incident angle before and after the heat treatment. The total color difference (E* ), lightness (L*), red-green index (a*), and yellow-blue index (b*), were investigated at different treatment conditions. The values of L* and b* decrease continuously with the increasing temperature and duration. The results of analysis of variance (two-way ANOVA) indicate that the heat treatment temperature has a significant effect on the colorimetric properties of the heat-treated young eucalyptus wood. The gloss decreased after the heat treatment for both perpendicular and parallel directions. ANOVA analysis showed that the treatment temperature duration have a significant effect on the parallel glossiness of 85°(p＜0.05). These are probably due to differences in surface roughness between untreated and heat-treated wood. To achieve the desired color like teak wood, the preferred temperature is no more than 185°C.

WOOD RESEARCH Volume 65, Number 4, 2020
HUICHUAN JIANG, QUANJI LU, GUANJUN LI, MIN LI, and JIANING LI

Effect of heat treatment on the surface color of rubber wood (Hevea brasiliensis)

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 (ΔE*), 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.