Sang-Bum Park

Fire Performance of the Wood Treated with Inorganic Fire Retardants

To prepare the eco-friendly fire retardant wood, Japanese red pine (Pinus densiflora), Hemlock (Tsuga heterophylla), and Radiata pine (Pinus radiata) were treated with inorganic chemicals, such as sodium silicate, boric acid, ammonium phosphate, and ammonium borate. Different combination and concentration of those chemicals were impregnated by vacuum/pressure treatment methods. The electron-beam treatment was used to increase the chemical penetration into the wood. The fire performance of the fire retardant treated wood was investigated. The penetration of chemicals into the wood was enhanced after electron beam treatment. Ignition time of the treated wood was the most effectively retarded by sodium silicate, ammonium phosphate, and ammonium borate. The most effective chemical combination was found at 50% sodium silicate and 3% ammonium borate, which satisfied flammability criteria for a fire retardant material in the KS F ISO 5660-1 standards.

Change of heating value, pH and FT-IR spectra of charcoal at different carbonization temperatures

ABSTRACT To understand transition characteristics from wood to charcoal, Quercus variabiliswood was carbonized at 200, 250, 300, 340, 540 and 740°C, respectively. Heating value, pH and surface property by FT-IR spectroscopy of the carbonized charcoal were investigated. Heating value and pH increased with increasing carbonization temperature from 4500 cal/g and 4.3 of the control wood to 8,000 cal/g and 9 of the char-coal carbonized at 740°C, respectively. From FT-IR spectroscopy, the peaks from O-H, C-H and C-O stretching disappeared during carbonization at 540 and 740°C. Aromatic skeletal vibration at near 1,506~1,593 cm -1 was repidly increased until 540°C. These results suggest that the chemical and physical characteristics of wood components in cell wall can be easily changed by increasing carbonization temper-ature and the carbonization seem to be incomplete at temperature below 540°C. Keywords : carbonization, charcoal, heating value, pH, FT-IR 1. INTRODUCTION Charcoal can be generally produced when wood is heated in the absence of oxygen. In this process, the water contained in the wood is first driven off before the wood constituents (cellulose, hemicellulose and lignin) begin to be thermally decomposed. Wood pyrolysis is a complex combination with the individual py-rolysis of cellulose, hemicellulose, lignin and extractives, each of which has its own charac-teristics (Kwon et al., 2009).Zeriouh and Belkbir (1995) reported that, in the pyrolysis process of wood constituents with heating rate of 5°C min

Bonding Quality of Cylindrical LVL and Surface Durability by Its Painting

In order to develop the end use of cylindrical laminated veneer lumber (LVL) such as wooden crafts, the water proof-bonding strength, the resistance to abrasion and the surface hardness by painting the surface of LVL were investigated. The study results were as follows; The water proof-bonding strength through 5 cyclic test by boiling in water immersion and drying were favorable without delamination of glue line. Then the formulation of glue was resorcinol resin (100) to hardener of paraformaldehyde (5) by mixed weight percentage. The resistance to abrasion was relatively higher at cross section than tangential section. When tangential section of LVL was painted by UV protection oil, the resistance to abrasion was improved. In case of an cross section of LVL, the higher surface hardness appeared at larch core than radiata pine LVL. Also, in case of an tangential section of LVL, the higher surface hardness appeared at glue line than veneer side.

편백잎추출수의 실내 가습시 휘발성유기화합물 방출 특성

건축재료와 생활용품으로부터 방출되는 실내공기 오염물질들로 인한 피해가 증가하고 있는 현시점에서 친환경 제품에 대한 관심이 높아지고 있다. 이러한 관심 속에 피톤치드에 대한 효능이 알려지면서 다양한 방법으로 사용되고 있다. 피톤치드를 다량 함유한 편백잎 증류추출수의 가습시 발생하는 휘발성유기화합물의 방...

Sound Absorption and Physical Properties of Carbonized Fiberboards with Three Different Densities

Characteristics of carbonized fiberboard such as chemical materials absorption, electromagnetic shielding, and electrical and mechanical performance were determined in previous studies. The carbonized board therefore confirmed that having excellent abilities of these characteristics. In this study, the effect of density on physical properties and sound absorption properties of carbonized fiberboards at were investigated for the potential use of carbonized fiberboards as a replacement of conventional sound absorbing material. The thickness of fiberboards after carbonization was reduced 49.9%, 40.7%, and 43.3% in low density fiberboard (LDF), medium density fiberboard (MDF), and high density fiberboard (HDF), respectively. Based on SEM images, porosity of carbonized fiberboard increased by carbonization due to removing adhesives. Moreover, carbonization did not destroy structure of wood fiber based on SEM results. Carbonization process influenced contraction of fiberboard. The sound absorption coefficient of carbonized low density fiberboard (c-LDF) was higher than those of carbonized medium density fiberboard (c-MDF) and carbonized high density fiberboard (c-HDF). This result was similar with original fiberboards, which indicated sound absorbing ability was not significantly changed by carbonization compared to that of original fiberboards. Therefore, the sound absorbing coefficient may depend on source, texture, and density of fiberboard rather than carbonization.

Structural Performance of Joints for Partial Reinforced Beam Using GFRP Laminated Plate and Cylindrical Reinforced LVL Column

After being laminated with a combination of glass fiber reinforced plastic and plywood, the GFRP laminated plate was densificated for 1 hour at with pressure of . A partial reinforced beam was produced by attaching the 5 GFRP laminated plates to the joint of glulam and the column. In addition, the column to beam joint was produced by using reinforced laminated wooden pin which was made of GFRP sheet and plywood, fiber glass reinforced cylindrical-LVL column. The joint was made of round log, glulam and drift pin as the reference specimen, and its moment resistance was evaluated. As a result, the strength performance of specimens with partial reinforced beams were 1.8 times stronger than the reference specimen on average. Furthermore, rupture was neither occurred on partial reinforced beam nor column. Toughness and stiffness of joints were also fine. The GFRP sheet reinforced laminated plate showed better reinforcement effect than GFRP textile reinforced one. GFRP sheet was inserted into each layer of laminate, and it showed good condition in rotation-angle and strength, therefore it is the most appropriate to reinforce the part of the beam.

Effect of Carbonization Temperature on Hygric Performance of Carbonized Fiberboards

ABSTRACT Increases of public attention on healthy environment lead to the regulation of indoor air quality such as Clean Healthy House Construction Standard. This standard covers emission of total volatile organic compounds (TVOCs) (e.g., formaldehyde, benzene, and toluene), ventilation, and use of environmentally-friendly products or functional products. Moisture absorption and desorption abilities are a recommended functionality for improving indoor air quality. In this study, moisture absorption and desorption capacities of carbonized board from wood-based panels and other materials were determined by using UNT-HEAT-01 according to ISO 24358:2008. Pine had higher moisture ab-sorption and desorption capacities (49.0 g/m 2 and 35.3 g/m, respectively) than hinoki cypress, cement board, gypsum board, oriented strand board, and medium density fiberboard (MDF). The moisture absorption and desorption capacities differed considerably according to the wood species. After carbonization process at 400℃, the absorption and de-sorption ability of MDF increased to 38% and 60%, respectively. However, moisture absorption and desorption capaci-ties decreased with increasing carbonization temperature, but they were still higher than original MDF.) Therefore, it is suggested that carbonization below 600℃ can improve moisture absorption/desorption capacities.

Combustion Characteristics of Bamboo Charcoal Boards

The fire retardant bamboo charcoal (BC) boards were manufactured for interior building materials in this study, The BC boards were manufactured by mixing and pressing of the bamboo charcoal, expanded vermiculite, and inorganic binder. The combustion behaviors of the BC boards were investigated using a cone calorimeter at an incident heat flux of 50 kW/. Three building materials (plywood, BC board of Japan, and gypsum board) were used to observe the burning behaviors of weight loss, total heat release rate, and maximum heat release rate. Surface test and toxicity evaluation of the BC board were also conducted. The weight loss of the BC board (12.0%) was lower than the nonflammable gypsum board (15.6%) after burning of 10 min. Total heat release of the BC was 3 MJ/ (KS standard 8 MJ/) and total heat release rate of the BC was 20 kW/ (KS standard 200 kW/). Therefore, the BC boards were adjustable for the third-grade flame retardant building materials. External appearance change and mouse toxicity were not found in the BC boards after the combustion test.

Comparative Study of the Storage Stability between a Melamine-Urea-Formaldehyde and a Urea-Formaldehyde Resin

Abstract Amino resin wood adhesives used for medium-density fiberboard (MDF), a melamine-urea-formaldehyde (MUF) resin and a urea-formaldehyde (UF) resin, were each synthesized with an overall formaldehyde/urea molar ratio of 1.10. The storage stability of the resins was monitored by their gel times and viscosity changes, as well as by a multiple light scattering method. The storage stability tended to be affected by the temperature at which the resins were stored. MUF resin had a higher storage stability at a storage temperature above room temperature, whereas UF resin exhibited the best storage stability at 10°C with overall good stability at all tested temperatures from 10°C to 40°C.

Developing of Sound Absorption Composite Boards Using Carbonized Medium Density Fiberboard

선행연구에서 다양한 목질 보드류를 열분해하여 다공질 탄화보드 제조에 성공하였고, 높은 난연성, 전자파차폐성, 원적외선방사, 폼알데하이드 흡착성, 흡음성능을 확인하였다. 본 연구에서는 경제성과 흡음성이 뛰어난 탄화 중밀도 섬유판(MDF)을 선택하여 보다 높은 흡음성능을 부여하기 위해 다른 흡음재료에도 사용 중인 샌딩처리와 타공기법을 시도하였다. 또한 개선된 흡음성능을 바탕으로 실제 음향판을 제작하여 그 음향적 효과를 파악하였다. 탄화 MDF를 십자모양(타공 5개), 직사각형모양(타공 9개), 일자모양(타공 5개)으로 타공 처리한 후, 흡음률을 측정한 결과, 무처리 탄화 MDF의 흡음률은 14% 정도를 나타내었고, 직사각형모양 타공 시편이 16.01%로 흡음률이 가장 높았고 십자모양 타공 시편이 15.68%, 일자 타공 시편은 14.25%의 흡음률을 나타내어 그 효과가 미미하였다. 반면에, 탄화 MDF의 표면을 각 1, 2, 3 mm로 표면샌딩 처리후 흡음률을 측정한 결과, 무처리 시편(13%)에 비해 65% 증가한 21.7% (1 mm 샌딩), 21.83% (2 mm 샌딩), 19.37% (3 mm 샌딩)를 확인하였다. 이 결과를 바탕으로 실대형 탄화보드 복합 음향판을 제작하였으며 잔향실법으로 흡음시험한 결과 감음계수 0.45로 높은 흡음성능을 발휘하여 상업화도 가능할 것으로 판단된다. 【In the previous study, a variety of wood-based panels was thermally decomposed to manufacture carbonized boards that had been proved to be high abilities of insect and fungi repellence, corrosion and fire resistant, electronic shielding, and formaldehyde adsorption as well as sound absorption performance. Based on the previous study, carbonized medium density fiberboard (c-MDF) was chosen to improve sound absorption performance by holing and sanding process. Three different types of holes (cross shape, square shape, and line) with three different sanding thickness (1, 2, and 3 mm) were applied on c-MDF and then determined sound absorption coefficient (SAC). The control c-MDF without holes had 14% of SAC, however, those c-MDFs with holes had 16.01% (square shape), 15.68% (cross shape), and 14.25% (line) of SAC. Therefore, making holes on the c-MDF did not significantly affect on the SAC. As the degree of sanding increased, the SAC of c-MDF increased approximately 65% on sanding treated c-MDFs (21.5, 21.83, and 19.37%, respectively) compared to the control c-MDF (13%). Based on these results, composite sound absorbing panel was developed with c-MDF and MDF (11 mm). The noise reduction coefficient of composite sound absorbing panel was 0.45 which was high enough to certify as sound absorbing material.】