• Journal of the Korean Wood Science and Technology
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• v.47 no.3
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• pp.253-264
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• 2019

This study characterized the chemical compounds in tannin from mangium (Acacia mangium) bark extract and determined the physical-mechanical properties of glued laminated timber (glulam) made from sengon (Falcataria moluccana), jabon (Anthocephalus cadamba), and mangium wood. The adhesives used to prepare the glulam were based on mangium tannin and phenol resorcinol formaldehyde resin. Five-layer glulam beams measuring $5cm{\times}6cm{\times}120cm$ in thickness, width, and length, respectively, were made with a glue spread of $280g/m^2$ for each glue line, cold pressing at $10.5kgf/cm^2$ for 4 h and clamping for 20 h. Condensed mangium tannin consisted of 49.08% phenolic compounds with an average molecular weight of 4745. The degree of crystallinity was 14.8%. The Stiasny number was 47.22%. The density and the moisture content of the glulams differed from those of the corresponding solid woods with mangium having the lowest moisture content (9.58%) and the highest density ($0.66g/cm^3$). The modulus of rupture for all glulam beams met the JAS 234-2003 standard but the modulus of elasticity and the shear strength values did not. Glulam beams made with tannin had high delamination under dry and wet conditions, but glulam made from sengon and jabon wood met the standard's requirements. All glulam beams had low formaldehyde emissions and were classified as $F^{****}$ for formaldehyde emissions according to the JAS 234 (2003) standard.

• Journal of the Korean Wood Science and Technology
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• v.32 no.2
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• pp.65-72
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• 2004

A melamine-urea-formaldehyde (MUF) resin, based on 5 percent melamine addition of the resin solids weight, was synthesized in the laboratory for particleboard (PB) manufacture. Laboratory PBs were made with the MUF resin at three press times (3, 4, 5 min) and two resin application rates (6, 8 percent). Enclosed caul system was used for collecting the exhaust gases materials generated during the hot-pressing of PBs. Exhaust gases materials generated inside the enclosed caul during the hot-pressing of PBs were collected in a controlled air stream. Formaldehyde from the exhaust gases collected was determined per a chromotropic method of the National Institute of Occupational Safety and Health Method 3500. The measurement results showed that formaldehyde emissions during the hot-pressing of PB significantly increased with increasing press time, and MUF resin application rates. PB' performance test results showed that internal bond (IB) of PB made with 3-minute press time exceeded the minimum requirement for KS F 3104 PB type 8.0.

• Journal of the Korean Wood Science and Technology
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• v.40 no.2
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• pp.101-109
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• 2012

Wood composites are a hygroscopic material and have ability to exchange its moisture content with air. This study investigated the formaldehyde emission and moisture content change of four wood composites (particleboard (PB), medium density fiberboard (MDF), high density fiberboard (HDF), laminated HDF (L-HDF)) as a function of bake-out temperature and time. The composites were baked out for 1, 3, 5, 7, 10, 14, 21, and 28 days at temperatures of $20{\pm}2$, $35{\pm}2$, and $50{\pm}2^{\circ}C$ in a dry oven. The moisture content change was used to determine the emission bake-out of the composites. Best bake-out time results were obtained with after 7 days all composites. Formaldehyde emission values of composites decreased with decreasing moisture content for both temperatures. The formaldehyde emission results of bake-out temperature 35 and $50^{\circ}C$ showed a similar tendency.

• Journal of the Korean Ceramic Society
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• v.46 no.6
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• pp.627-632
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• 2009

Formaldehyde emissions from the construct was harmful to human. Diatomite, bentonite and zeolite were used as porous materials for fabricating panels. Formaldehyde adsorption and physical characteristics of porous materials were investigated and hydrothermal method was applied to fabricate panels. Formaldehyde adsorption contents of panels with porous materials were higher than that of panel without porous materials. The panels with Cheolwon diatomite and Pohang zeolite showed excellent characteristics of Formaldehyde adsorption. These characteristics were caused by higher surface area and pore volume of porous materials. Formaldehyde adsorption contents were influenced by surface area and pore volume of panels. Correlation coefficient between surface area and Formaldehyde adsorption content of panels was 0.87. The panels with porous materials had higher strength than that without porous materials because of bridging role particles.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.1
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• pp.1-9
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• 2013

Hazardous Air Pollutants (HAPs) are difficult to measure, analyze and assess for risk because of low ambient concentrations and varieties. Types of HAPs are Volatile organic compounds (VOCs), Polycyclic aromatic hydrocarbon (PAHs) and Aldehydes. HAP emissions from vehicles are a contributor to serious adverse health effects in urban areas. In this study, hazardous air pollutant emissions from road transport vehicles by Non-methane volatile organic compounds (NMVOC) weight fraction and PAHs emission factors are estimated in 2008. The top-five-most hazardous air pollutant emissions were estimated to toluene 864.3 ton/yr, acrolein 690.6 ton/yr, acetaldehyde 554.5 ton/yr, formaldehyde 498.7 ton/yr, propionaldehyde 421.6 ton/yr in 2008. The results for a cancer and non-cancer risk assessment of HAPs emissions show that the major cancer driver is formaldehyde and the non-cancer driver is acrolein.

• Journal of ILASS-Korea
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• v.23 no.4
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• pp.175-184
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• 2018

Emission characteristics of regulated (NOx, PM, CO, NMHC) and unregulated (VOCs, aldehydes, PAHs) air pollutants were investigated for diesel heavy duty buses equipped with different after-treatment systems (DPF+EGR and SCR) under urban driving cycle. The combustion temperature and the working temperature of SCR catalysts were important to make impact on NOx emissions, whereas PM emissions were low. The alkane groups dominated NMVOCs emissions, making 42.6~59.4% of sum of the NMVOCs emissions. Especially, alkane emissions of DPF+EGR-equipped vehicle included DOC had 14.9~15.5% higher than those of SCR-equipped vehicle due to low efficiency of oxidation catalyst. In the case of individual NMVOCs, n-nonane and propylene emissions highly occupied for DPF+EGR and SCR, respectively. Formaldehyde emissions among aldehydes were the highest and PAHs emissions were hardly detected except naphthalene and phenanthrene. The NMHC speciation has been shown to be the highest of the formaldehyde ranged 20.8~21.5%. The results of this study will be contributed to establish Korean HAPs emission inventory for automobile source.

• Journal of the Korean Wood Science and Technology
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• v.33 no.2 s.130
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• pp.29-39
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• 2005

Formaldehyde emissions from wood-based panels bonded with pine and wattle tannin-based adhesives, urea-formaldehyde resin (UF), melamine-formaldehyde resin (MF), and co-polycondensed resin of urea-melamine-formaldehyde (UMF) were measured by the Japanese standard method using a desiccator (JIS A 1460) and the EN 120 (European Committee For Standardization, 1991) method using the perforator value. In formaldehyde emission, all particleboards made using the wattle tannin-based adhesive with three different hardeners, paraformaldehyde, hexamethylenetetramine, and tris(hydroxyl)nitromethan (TN), satisfied the requirements of grade $E_1$. But only those made using the pine tannin-based adhesive with the hexamine as hardener met the grade $E_1$ requirements. Hexamine was effective in reducing formaldehyde emission in tannin-based adhesives when used as the hardener. While the UF resin showed a desiccator value of $7.1mg/{\ell}$ and a perforator value of 12.1 mg/100 g, the MF resin exhibited a desiccator value of $0.6mg/{\ell}$ and a perforator value of 2.9 mg/100 g. According to the Japanese Industrial Standard and the European Standard, the formaldehyde emission level of the MDF panels made with UF resin in this study came under grade $E_2$. The formaldehyde emission level was dramatically reduced by the addition of MF resin. The desiccator and perforator methods produced proportionally equivalent results. Gas chromatography, a more sensitive and advanced method, was also used. The samples for gas chromatography were gathered during the experiment involving the perforator method. The formaldehyde contents measured by gas chromatography were directly proportional to the perforator values.

• Analytical Science and Technology
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• v.24 no.4
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• pp.282-289
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• 2011

Rapid screening method for the determination of the emissions of pollutants from vehicle interior parts and materials have been developed as ISO 12219-2 which is using bag and based on a static condition. The method was not controlled humidity in the test bag, so it is not suitable test method for formaldehyde emission test which is highly related to humidity condition. In this study, possibility of control humidity in the static test bag by adding extra water and the effect of humidity condition for formaldehyde emissions have been investigated. The relative humidity in the test bag was affected not only amount of water added also material of test bag and test specimen. The emission intensity of formaldehyde was increased according to increasing relative humidity in test bag. But excessively supplied water was condensed on the inner surface of test bag and surface of sample specimen that were sorption formaldehyde and were reduced its emission intensity.

• Journal of the Korean Wood Science and Technology
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• v.39 no.5
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• pp.451-458
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• 2011

Adhesives derived from renewable resources allow wood panel producers to make lower cost alternatives to formaldehyde-based adhesive resins. Among them, adhesive components extracted from industrial by-products or wastes are the most important research fields in the efficient utilization of waste and cost reduction. In our study, the rapeseed flour, which is a by product from the production of biodiesel extracted from rapeseed, was introduced to develop alternative adhesives for the production of wood flooring. The rapeseed flour was hydrolyzed with 1% sodium hydroxide solution and PF prepolymers were prepared with 3-molar ratios, 1.8, 2.1 and 2.4. The linear fracture mechanics was introduced to evaluate the glue bond quality in wood flooring composed of fancy-veneered and plywood, and the formaldehyde emission and adhesive penetration were also investigated. The formaldehyde emissions of wood flooring met the requirement of the standard of $SE_0$ specified in the KS standard. The rapeseed flour adhesive penetrated sufficiently into the vessel elements and lumens in fancy veneer and plywood and gave strong bond quality to the wood flooring. The fracture mechanics was introduced to evaluate the adhesive joint between fancy veneer and plywood. The critical stress intensity factor ($K_{IC}$) of boliva overlayed wood flooring was increased with increasing molar ratio and this was the same tendency in oak overlayed wood flooring. From the results, the formulated adhesives were efficiently used to bond fancy veneer onto the plywood to make wood flooring and showed a potential to be used as a component of environmentally friendly adhesive resin systems for production of flooring.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.388-396
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• 2009

In our study, the potential of okara as an ingredient of new bio-based adhesives was investigated for the production of fancy-veneered flooring boards. Okara was hydrolyzed by 1% sulfuric acid solution (AC) and 1% sodium hydroxide solution (AK). Phenol formaldehyde (PF) prepolymers were prepared as a cross-linker of okara hydrolyzates. Then, okara-based adhesive resins were formulated with 35% AC, 35% AK and 30% PF prepolymer on solid content basis. The adhesive resins were applied on high-density fiberboards (HDF) with the spread rate of $300g/m^2$. After that, oak fancy veneers are covered on the HDF, and then pressed with the pressure of $7kg/m^2$ at $120^{\circ}C$. The experimental variables were three mole ratios of formaldehyde to phenol (1.8, 2.1, 2.4), three assembly time (0, 10, 20 min), and two press time (90 sec, 120 sec), respectively. The fancy-veneered high-density fiberboards were tested by dry tensile strength, glueline failure by wetting and formaldehyde emission. Tensile strength of the boards exceeded the requirement of KS standard. The formaldehyde emissions were approached at the E0 level specified in KS standard. Based on these results, okara can be used as an ingredient of environmentally friendly adhesive resin systems for the production of flooring boards.