• Journal of the Korean Wood Science and Technology
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• v.37 no.6
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• pp.505-516
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• 2009

The effects of wood species, particle size of wood flours and coupling treatment on the mechanical properties of wood plastic composites (WPC) are investigated in this study. Chemical components of wood flour from 3 different wood species were analyzed by the chemical analysis. Wood flours of 40~60 mesh and 80~100 mesh were manufactured from Larix (Larix kaempferi Lamb.), Quercus (Quercus accutisima Carr.), and Maackia (Maackia amuresis Rupr. et Maxim). The wood flours were reinforced into polypropylene (PP) by melt compounding and injection molding, then tensile, flexural, and impact strength properties were analyzed. The order of alpha-cellulose content in wood is Quercus (43.6%), Maackia (41.3%) and Larix (36.2%). The order of lignin content in wood is Larix (31.6%), Maackia (24.7%), and Quercus accutisima (24.4%). The content of extractives in wood is in the order of Larix (8.5%), Maackia (4.4%), and Quercus accutisima (3.9%). As the content of alpha-cellulose increases and the lignin and extractives decreases, tensile and flexural strengths of the WPC increase. At the same loading level of wood flours, the smaller particle size (80~100 mesh) of wood flours showed highly improved tensile and flexural strengths, compared to the larger one (40~60 mesh). The impact strength of the WPC was not significantly affected by the wood species, but the wood flours of larger particle size showed better impact strengths. The addition of maleated polypropylene (MAPP) provided the highly improved tensile, flexural and impact strengths. Morphological analysis shows improved interfacial bonding with MAPP treatment for the composites.

• Journal of the Korean Wood Science and Technology
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• v.45 no.3
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• pp.288-296
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• 2017

In this study, the effect of spray-drying conditions and surfactant addition on the spray-drying yield, morphological characterization, size distribution and re-dispersity in water of spray-dried lignocellulose nanofibril (LCNF) were investigated. The freeze-dried LCNF after solvent exchange had linear fiber morphology with a diameter of 70-300 nm, and the spray-dried LCNF showed rod-like particle morphology. The spray-drying yield and particle size of spary-dried LCNF at $140^{\circ}C$ was highest and smallest, respectively. As LCNF concentration and blowing rate decreased and increased, respectively, the spray-drying yield and particle size were increased. The highest spray-drying yield was found at distearyl dimethyl ammonium chloride (DDAC) addition of 10 phr at $140^{\circ}C$. As the particle size decreased and the DDAC content increased, filtration time of spray-dried LCNF in water was decreased and increased, respectively.

• Journal of the Korean Wood Science and Technology
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• v.40 no.1
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• pp.1-9
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• 2012

Densified fuels from biomass are widely used in North America and Europe as a regenerable and clean bioenergy. In this study, the fuel characteristics and densification characteristics of Japanese larch and Hyunsasi poplar were studied using a piston-type briquetting machine. The effects of pressure, pressure holding time, species, and particle size on briquette characteristics were studied. At room temperature, the highly densified briquettes of Japanese larch and Hyunsasi poplar can be produced at a compression pressure of 110~170 MPa. The produced briquettes have densities between 0.66 and 0.94 g/$cm^3$ after 28 days of storage at room temperature. The optimum pressure holding time was found to be 12 seconds. There is a linear increase in pressure with increase in density. The densities of briquettes from Japanese larch were higher than those of briquettes from Hyunsasi poplar. Also, the coarser particle size resulted in higher densities in briquettes than the finer particle size.

• Journal of the Korean Wood Science and Technology
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• v.33 no.6 s.134
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• pp.46-54
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• 2005

To make the composite panels of wood particles and recycled plastics, the recycled polypropylene was used. In the composite panels the sizes of wood particles were 1/32", 1/4" and 1/2" mesh, and the composition ratios of the recycled plastics were 10%, 30%, 50% and 70%. The physical and mechanical properties of the composite panels were investigated. As the composition ratio of wood particle increases, the density increases, while it decreases at the same composition ratio because the size of wood particle increases. As the composition ratio of recycled polypropylene increases from 10% to 30%, both thickness swelling and water adsorption significantly decrease. As the composition ratio of recycled polypropylene increases, the modulus of rupture in bending strength increases, but the modulus of elasticity in bending strength decreases. SEM shows that the dissolved recycled polypropylene penetrates into tracheid and pit, and bonds mechanically to other wood particle and matrix to increase the bonding strength and improve the physical and mechanical properties of composite panel.

• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.166-171
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• 2016

Size reduction is one of the major pre-processing operations in using biomass as a source of energy or raw materials for forest products industry. The grinding characteristics of dried yellow poplar wood chips were investigated using laboratory knife mill with three different screen aperture diameters to provide the basic information for the optimizing of size reduction processes in biomass industry. Average specific energy consumptions were 0.157, 0.137, and 0.093 Wh/g for the screen aperture diameters of 5.0, 7.5, and 9.0 mm, respectively. According to the results of size distribution analysis of ground particles, the sizes of the most of ground particles were much smaller than the aperture diameters of the screens installed on knife mill used in this study.

• Journal of the Korean Wood Science and Technology
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• v.52 no.4
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• pp.363-374
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• 2024

Nyamplung (Calophyllum inophyllum L.) seeds, which account for 40% of the fruit, have been used as a raw material for biofuels, and the seed shells remaining after their extraction are wasted. In this study, we investigated the potential of waste Nyamplung seed shells in the form of pellets as a biomass energy resource. A completely randomized research design was implemented to evaluate the effects of torrefaction and heat treatment on the quality of produced pellets. Two observed treatments, namely, particle size (0.18-0.25, 0.25-0.43, and 0.43-0.84 mm) and torrefaction temperature (200℃, 225℃, and 250℃), were investigated. Our results showed that the calorific value of torrefied Nyamplung seed-shell pellets ranged from 4,245.60 to 4,528.00 cal/g, fulfilling the Indonesia Nasional Standard (≥ 4,000 cal/g). The quality of pellets were the best when produced from raw materials with a particle size of 0.18-0.25 mm and torrefaction temperature of 225℃. Thus, we concluded that waste Nyamplung seed shells are a good raw material for the production of pellets.

• Journal of the Korean Wood Science and Technology
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• v.35 no.2
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• pp.69-78
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• 2007

The mechanical properties of wood flour, Hwangto (325 and 1,400 mesh per 25,4 mm) and coupling agent-reinforced HDPE composites were investigated in this study. Hwangto and maleated polyethylene (MAPE) were used as an inorganic filler and a coupling agent, respectively. The addition of Hwangto and MAPE to virgin HDPE also increased the Young's modulus in the smaller degree. The addition of wood flour and Hwangto to virgin HDPE increased the tensile strength, due to the high uniform dispersion of HDPE by high surface area of Hwangto in HDPE and wood flour. MAPE also significantly increased the tensile strength. When wood flour was added, there was no notable difference on the tensile properties, in terms of Hwangto particle size. Hwangto also improved the flexural modulus and strength of reinforced HDPE composites. With different particle sizes of Hwangto, there was no considerable difference in flexural modulus and strength of reinforced HDPE composites. The addition of Hwangto showed slightly lower impact strength than that of wood flour. However, the particle size of Hwangto showed no significant effect on the impact strength of reinforced composites. In conclusion, reinforced HDPE composites with organic and inorganic fillers provide highly improved mechanical properties over virgin HDPE.

• Journal of the Korean Wood Science and Technology
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• v.43 no.5
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• pp.672-681
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• 2015

As a part of abating the formaldehyde emission of amino resin-bonded wood-based composite panels, this study was conducted to investigate hydrolytic stability of urea-melamine-formaldehyde (UMF) resin depending on various hydrolysis conditions and hardener types. Commercial UMF resin was cured and ground into a powdered form, and then hydrolyzed with hydrochloric acid. After the acid hydrolysis, the concentration of liberated formaldehyde in the hydrolyzed solution and mass loss of the cured UMF resins were determined to compare their hydrolytic stability. The hydrolysis of cured UMF resin increased with an increase in the acid concentration, time, and temperature and with a decrease in the smaller particle size. An optimum hydrolysis condition for the cured UMF resins was determined as $50^{\circ}C$, 90 minutes, 1.0 M hydrochloric acid and $250{\mu}m$ particle size. Hydrolysis of the UMF resin cured with different hardener types showed different degrees of the hydrolytic stability of cured UMF resins with a descending order of aluminum sulfate, ammonium chloride, and ammonium sulfate. The hydrolytic stability also decreased as the addition level of ammonium chloride increased. These results indicated that hardener types and level also had an impact on the hydrolytic stability of cured UMF resins.

• Journal of the Korean Wood Science and Technology
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• v.50 no.4
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• pp.256-271
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• 2022

Activated carbon (AC) derived from coconut shells (CS-AC) was obtained through pyrolysis at 700℃ and subsequently activated with H₃PO₄. AC was ground in a Wiley mill several times to form powder particles at particle scales of 80, 100, and 200 meshes. The characterization of the AC was studied using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FT-IR), and surface area analysis (S_BET). The CS-AC-200 mesh resulted in a higher percentage of mesopores and surface area. This particle size had a larger surface area with angular, irregular, and crushed shapes in the SEM view. The smaller particles had smoother surfaces, less wear, and increased curing depth and ratio of the hardness of the resin composite. Based on the characterization results of the AC, it is evident that CS-AC with a 200 mesh particle size has the potential to be used as a filler in biocomposites.

• Journal of the Korean Wood Science and Technology
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• v.40 no.6
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• pp.445-453
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• 2012

In this study the effects of particle size and water content on the yields and physical/chemical properties of pyrolytic products were investigated through fast-pyrolysis of yellow poplar. Water content was critical parameters influencing the properties of bio-oil. The yields of bio-oil were increased with decreasing water content. However, the yield of pyrolytic product was not clearly influenced by feedstock's particle size. The water content, pH and HHV (Higher Heating Value) of bio-oil were measured to 20~30%, 2.2~2.4 and 16.6~18.5MJ/kg, respectively. The water content of feedstock was clearly influenced to water content of bio-oil. In terms of bio-char, HHV of them were measured to 26.2~30.1 MJ/kg with high content of carbon over 80%.