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 65, Number 5, 2020
Liyan Ma, Lina Wang, Xiaojun Ma, and JIANING LI

In situ hydrothermal synthesis of MnO2 nanowires/wood derived activated carbon hollow fibers composite and its application in supercapacitor

Composite electrode material composed of MnO2 nanowires and wood-derived activated carbon hollow fibres (Mn@ACHFs) was successfully fabricated by in situ hydrothermal method. In this work, MnO2 nanowires were developed by adjusting the mass ratio of potassium permanganate and wood activated carbon hollow fibres (ACHF). The ACHF with hierarchical porous structure served not only as the support for the growth of MnO2 particles, but also as the electric double layer capacitance for the composite electrode. The Mn@ACHFs exhibited an outstanding specific capacitance of 420 F.g-1 at 1 A.g-1 and cycle stability with 99.7% capacitance retention after 5000 cycles at 5 A.g-1. Electrochemical characteristics of the prepared composites are attributed to the synergetic effect of the double layer capacitance of the hierarchical porous ACHF and the layered structure of MnO2, which can efficiently enhance the conductivity and stability of the electrodes.

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.

WOOD RESEARCH Volume 66, Number 1, 2021
Dongna Li, JIANING LI, and Xiaojun Ma

Study on the structure and properties of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/ rubber wood fiber composites modified with titanate coupling agent

In this study, the biodegradable composites were prepared from rubber wood fibers (Hevea brasiliensis) and biopolymer poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) via hot pressing process, using the titanate as the coupling agent. The morphological, chemical structure, mechanical properties and water absorption (WA) of the composites were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), mechanical properties and WA analysis. Results showed that a new absorption peak of Ti-O-C was formed due to the addition of titanate, indicating that it was successfully grafted on the surface of wood fibers. In addition, the mechanical properties of the composites first increased and then decreased with the increasing of the titanate content. The obvious improvement of WA of composites was attributed to the inclusion of P34HB by titanate modified wood fiber. Moreover, it was also found that the optimal condition of the titanate coupling agent content was 1 wt%.