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This study investigated the anatomical and non-anatomical characteristics of six wood species, Acacia mangium, Acacia hybrid, Dillenia pentagyna, Anacardium occidentale, Hevea brasiliensis, and Melaleuca cajuputi, from a plantation in Vietnam. The anatomical characteristics and non-anatomical characteristics were observed following the International Association of Wood Anatomists (IAWA) list. All species showed diffuse porosity and non-septate fibers. Exclusively solitary vessels were only observed in M. cajuputi. Vestured pits were observed in A. mangium, A. hybrid, and M. cajuputi, and tyloses were found in A. occidentale and H. brasiliensis. We observed vasicentric axial parenchyma in A. mangium, A. hybrid, A. occidentale, and H. brasiliensis, whereas diffuse axial parenchyma was observed in D. pentagyna and M. cajuputi. Further, prismatic crystals in the axial parenchyma cells existed in A. mangium, A. hybrid, and H. brasiliensis, and raphides in ray cells were observed in D. pentagyna. Silica bodies in ray cells were found in A. occidentale and M. cajuputi. H. brasiliensis exhibited the greatest vessel diameter and ray height, with D. pentagyna exhibiting the greatest fiber length and wall thickness. All the species showed considerable differences in heartwood fluorescence, water and ethanol extract colors, and froth test reactions.

Fire-retardant performance was imparted to the existing wood-fiber insulation boards (WIB) via internal and external treatment with silica- and phosphorus-based fire-retardants. The combustion and smoke characteristics were investigated using a cone calorimeter. Based on combustion for 600 s, the weight loss and shrinkage of WIBs decreased due to fire-retardant treatment. The time to ignition was delayed to more than 400 s on the WIBs treated internal and external fire- retardant (WIB-IEs), whereas that of WIB with only internal treatment (WIB-I) was 5 s. The overall heat release rate (HRR), HRRpeak, and total heat release (THR) of WIB-IE specimens decreased, and the fire resistance standard Class II was satisfied. The WIB-IE2 showed higher fire resistance performance, with a HRRmean level of 6.7 kW/m2 and a THR of 1.3 MJ/m2. The WIB-I showed extremely low total smoke release (TSR) compared to the external fire-retardant treated specimen. However, the externally treated WIB-IEs had an increased TSR of 165 to 256 m2/m2 due to the increase in incomplete combustion caused by the fire-retardant. After fire-retardant treatment, CO2 generation decreased because the rate of complete combustion decreased, but CO emission increased slightly. Therefore, silica- and phosphorus-based fire-retardants by internal and external treatments were suitable for WIBs.

The demand for noise control in residential environments is steadily increasing, but the currently available noise-reducing materials used in walls and floors are unsustainable and expensive. As an alternative, wood-fiber could be a good resource to manufacture eco-friendly acoustic materials. In this study, fiberboards were prepared by mixing wood-fibers (Pinus densiflora) with melamine-urea-formaldehyde resin adhesive, obtaining specimens with different final densities and resin contents. The acoustic, physical, and morphological properties of the fiberboards were investigated. The sound absorption was greatly influenced by the density of the fiberboard: lower densities showed higher sound absorption performances. Furthermore, the low-frequency absorption coefficient was higher for lower resin contents. The materials met all the criteria required by the Korean standards for fiberboards. As the density increased, the dimensional stability and the bending strength increased; in contrast, the physical properties were not affected by the resin content. Microscopy observations confirmed that specimens with different densities and resin contents had different porosities; the porosity was assumed to be the main property that governs the noise-reducing ability. Due to their eco-friendliness and inexpensiveness, these fiberboards offer themselves as efficient and effective alternative sound-absorbing materials.

As petrochemical products (including plastics) contribute to the destruction of the natural environment, the use of such products must be reduced. Plastics account for 90% of the insulation materials used in Korea, including extruded polystyrene (EPS), expanded polystyrene (XPS), and urethane foam. Wood-fiber insulation board (WIB) is a promising natural alternative to petrochemical insulation. This study aimed to determine the optimal amount of adhesive resin required for manufacturing WIB. Fire-resistant WIB was prepared with a melamine-urea-formaldehyde (MUF) resin (ranging from 20% to 35%), and the physicochemical and fire-resistant properties were determined. Higher resin content led to improved physical properties, while the thermal conductivity was unaffected. With the exception of 35% resin content in the WIB, the formaldehyde emissions of the WIB samples complied with the Korean Industrial Standards requirements for Super E0 grade (less than 0.3 mg per L). The physicochemical properties of the WIB samples were sufficient for use as an insulating material, even at 20% resin content. A perpendicular flame test revealed that all samples formed a carbonized layer to prevent flame penetration, except for the specimen with 20% of the resin content. The cone calorimeter testing indicated that the MUF adhesives acted as an effective fire retardant at resin contents above 25%.

Potential application of Sembilang bamboo (Dendrocalamus giganteus) as a fuel source or an adsorbent was investigated, due to its large diameter, fast growth speed, and growth type. Samples of D. giganteus were carbonized at various temperatures, and then their physicochemical, fuel, and adsorption properties were analyzed and compared to the properties of Moso bamboo (Phyllostachys edulis), which is widely used as a raw material for charcoal in Northeast Asia. The volume, weight, and density of the D. giganteus samples were greatly reduced between carbonization temperatures of 200 °C and 400 °C. It is possible that the high levels of SiO2 and K in D. giganteus may cause a high electric conductivity value in Dendrocalamus giganteus charcoal, which is a poor fuel source because of its high ash content and low calorific value. The acidity of D. giganteus disappeared at a carbonization temperature of 400 °C and the pH of D. giganteus increased up to 10.3. The adsorption power of D. giganteus, in terms of iodine and methylene blue, was higher than that of P. edulis. Based on the results of this experiment, the proper utilization of Sembilang bamboo charcoal was suggested as a chemical adsorbent.

Bamboo can be used in a variety of ways, including as fuel and as household and construction materials. Due to its versatility, the material is of high economic value. This study investigated the fuel properties of six bamboo species grown in Indonesia. Each bamboo sample was carbonized at different temperatures. Proximate and ultimate analyses were carried out on the bamboo samples. The thermal maturity of the bamboo samples as a solid fuel was investigated by the van Krevelen diagram. The efficiency of bamboo at each carbonizing temperature was determined based on the char yield, energy densification rate, energy efficiency, and calorific value. The results showed that the ash and fixed carbon contents of carbonized bamboo increased with an increasing carbonization temperature; while the volatile matter decreased. Significant changes in the fuel properties were observed between 200 °C and 400 °C. Carbonized bamboos showed lower sulfur contents in comparison to other fossil fuels. Ampel bamboo showed a calorific value of 18 MJ/kg to 32 MJ/kg, which was the highest value among the samples. Bamboo carbonized at temperatures above 600 °C showed a thermal maturity of coal grade. The results of this study can be used for utilizing Indonesian bamboo as a fuel source.

The tensile properties and impact strength of wood flour-polypropylene composite with or without impact modifier and coupling agent have been investigated. The addition of maleic anhydride and dicumyl peroxide improved the tensile properties and impact strength. With increasing ethylene–propylene rubber (EPR) and maleic anhydride (MAH)–modified ethylene–propylene rubber (MEPR), impact strength were increased, whereas tensile strength and Young’s modulus were decreased. At the same EPR or MEPR content, the higher filler loadings resulted in higher Young’s modulus and lower impact strength. Tensile properties and impact strength were greatly improved by adding EPR combined with maleic anhydride–grafted polypropylene (MAPP) and dihydroquinoline.

The objective was to evaluate the effect of temperature and clamping method during heat treatment on the properties of high density Okan wood. Heat treatment of sapwood and heartwood was conducted using an electric oven with a programmable controller at 160 °C, 180 °C, 200 °C, and 220 °C for 2 h. Physical and mechanical properties were compared before and after the heat treatment process. The color change (E*), weight loss, and volume shrinkage increased with increasing temperature, whereas the equilibrium moisture content (EMC) and water absorption (WA) decreased in both types of wood. The wood density was not affected by temperature, and the magnitude of E* in sapwood was the highest, while the magnitude of weight loss, volume shrinkage, EMC, and WA in heartwood was higher than in sapwood. The clamping method affected E* in heartwood only, while the weight loss, volume shrinkage, EMC, and WA was affect in both types of wood. A significant reduction in the mechanical properties occurred after heat treatment at 200 °C and 220 °C. The reduction of MOR, MOE, and shear strength in heartwood was greater than in sapwood, while the compressive strength reduction in sapwood was the highest.