국내산 잣나무와 낙엽송의 재질

권성민,황원중,권구중,김남훈 江原大學校 森林科學硏究所 2004 Journal of Forest Science Vol.20 No.-

국산 잣나무와 낙엽송의 비중, 연륜폭, 만재율, 종압축강도, 횡압축강도 및 전단강도를 측정하고 방사 ?향의 병이를 조사하여 다음의 결과를 얻었다. 1) 비중은 잣나무가 0.48로 낙엽송의 0.88보다 약 2배정도 낮은 값을 보였다. 두 수종 모두 수심에서 낮은 값을 보여주고 그 후 약 15연륜 까지 다소 증가하다가 일정해지는 경향을 보여주었다. 2) 연륜폭은 잣나무 3.43㎜, 낙엽송 2.83㎜로 잣나무가 낙엽송에 비해 넓었으며, 만재율은 잣나무 30%, 낙엽송 47%로 낙엽송이 잣나무에 비해 높았다. 두 수종 모두 만재율이 커짐에 따라 비중은 커지는 경향을 나타냈다. 3) 종압축강도와 종압축 비례한도, 종압축 영계수는 잣나무가 각각 300kgf/㎠, 270kgf/㎠, 9.2×10³kgf/㎠로서 낙엽송의 600kgf/㎠, 550kgf/㎠, 20×10³kgf/㎠에 비해 모두 낮은 수치를 나타내었다. 종압축강도, 종압축 비례한도 및 영계수의 방사방향변이는 두 수종 모두 뚜렷한 경향을 보이지 않았다. 4) 방사단면의 전단강도는 잣나무가 51kgf/㎠, 낙엽송이 69kgf/㎠으로 낙엽송이 컸으며, 접선단면은 잣나무가 56kgf/㎠, 낙엽송이 86kgf/㎠으로 낙엽송이 큰 값을 나타내었다. Density, annual ring width, latewood percentage and compressive properties of Pinus koraiensis and Larix kaempferi grown in Research Forest of Kangwon National University were measured and their radial variations were investigated. Density(Wa/Va) of Pinus koraiensis and Larix kaempferi was 0.48g/cm² and 0.88g/cm², respectively. Density of both species was slightly lower at pith area, increased gradually with cambial age up to about 15 years and then became constant. Annual ring width of both species was 3.43㎜ and 2.83㎜, respectively. Annual ring width of both species was irregular at pith area but regular after about 20 years. Latewood percentage of both species was 30% and 47%, respectively. Latewood percentage of Pinus koraiensis and Larix kaempferi increased with cambial age up to 14 years and 10 years, respectively and then became constant. Compressive strength, proportional limit and Young's modulus parallel to the grain of Pinus koraiensis were 330 kgf/cm², 270 kgf/cm² and 9.2×10³ kgf/cm², and those of Larix kaempferi were 600 kgf/cm², 550 kgf/cm² and 20×10³ kgf/cm², respectively. Shearing strength in radial direction of Pinus koraiensis and Larix kaempferi was 51 kgf/cm² and 69 kgf/cm², and that of tangential direction was 56 kgf/cm² and 86 kgf/cm², respectively. In this study, compressive and shearing properties of both species did not show any significant differences between juvenile wood and adult wood. Both species showed significant differences in the measured values.

Tailoring the characteristics of carbonized wood charcoal by using different heating rates

Kwon, Gu-Joong,Kim, Dae-Young,Oh, Choong-Hyeon,Park, Byung-Ho,Kang, Joo-Hyon Korean Physical Society 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.10

This study examined the characteristics of charcoals generated from White Lauan (Pentacmecontorta) and Punah (Tetrameristaglabra) by using different carbonization temperatures and heating rates. The scanning electron micrographs showed vestured pits in the White Lauan and raphide crystals in Punah as their respective anatomical characteristics. A slower heating rate resulted in a lower temperature to obtain the same amount of weight loss, regardless of the species being tested. A greater charcoal yield was obtained at a higher heating rate. The specific surface area was smaller in the charcoal produced at a higher carbonization temperature, but the heating rate had little effected. For both wood species, the axial compressive strength of the charcoal increased as the carbonization temperature was increased. The X-ray diffractograms of White Lauan and Punah woods heated at 1200A degrees C indicated thermal decomposition of the crystal structure of cellulose, but no appreciable structural changes occurred under the tested heating rate conditions. Overall, the heating rate affected the charcoal yield but not the specific surface area, compressive strength, and crystal structure.

Study on the nanofiberization of the giant miscanthus (Miscanthus sacchariflorus)

Gu Joong Kwon,Min Young Kim,Ji Wook Yang,Dae Young Kim,Seung Hwan Lee 강원대학교 산림과학연구소 2018 강원대학교 산림과학연구소 학술대회 Vol.2018 No.09

As an alternative biomass, the giant miscanthus was introduced for raising the bio industry in Korea. Unlike the expectations, however, its application has been limited due to its low economical value. To utilize it as a high added value material, in this study, the feasibility of nanofiber production from giant miscanthus holocellulose treated with delignification by peracetic acid method and their properties were investigated. The yield of the cellulose nanofiber produced by the acid hydrolysis method using sulfuric acid was calculated on the base of percentage of moisture content of the obtained suspension. As results, the yields were affected by sulfuric acid concentration, reaction time and temperature. The higher the reaction temperature, the smaller the length and width of the fiber were observed by TEM analysis. In addition, TEMPO oxidized giant miscanthus cellulose fiber treated with ball mill was shorter in fiber length than that of by homogenizer treatment. Moreover, the particle size was manufactured with uniform size with increase of the ball mill and homogenizer processing speed and time. In the FT-IR analysis, the carboxylation reaction of cellulose was confirmed. It was confirmed by X-ray diffraction analysis that the intensity of 002 was shifted after the ball mill and homogenizer treatment of TEMPO oxidized giant miscanthus cellulose.

Structural properties and adsorption capacity of holocellulose aerogels synthesized from an alkali hydroxide-urea solution

Kwon, Gu-Joong,Kim, Dae-Young,Hwang, Jae-Hyun,Kang, Joo-Hyon Korean Physical Society 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.10

A tulip tree was used to synthesize a holocellulose aerogel from an aqueous alkali hydroxide-urea solution with the substitution of an organic solvent followed by freeze-drying. For comparison, the synthesized holocellulose aerogels were divided into two groups according to the source of the hydrogel, an upper suspended layer and a bottom concentrated layer of the centrifuged solution of cellulose and NaOH/urea solvents. We investigated the effects of the temperature of the pre-cooled NaOH/urea solution (i.e., dissolution temperature) on the pore structure and the adsorption capacity of the holocellulose aerogel. A nano-fibrillar network structure of the holocellulose aerogel was observed, with little morphological difference in pore structure for different dissolution temperatures. Both micropores and mesopores were observed in the holocellulose aerogel. The specific surface area of the holocellulose aerogel was generally greater at lower dissolution temperatures. In a series of adsorption tests using methylene blue, the holocellulose aerogel showed the greatest adsorption capacity at the lowest dissolution temperature tested (-2A degrees C). However, the dissolution temperature generally had little effect on the adsorption capacity. The holocellulose aerogel produced from the upper suspended layer of the centrifuged hydrogel solution showed a greater porosity and adsorption capacity than the one produced from the bottom concentrated layer. Overall, the aerogel made by utilizing a delignified tulip tree display a high surface area and a high adsorption property, indicating its possible application in eco-friendly adsorption materials.

Pyrolysis of cellulose by CO2 Laser

( Gu Joong Kwon ),( Masahisa Wada ),( Shigenori Kuga ),( Keko Hori ),( Mitsuyoshi Yatagai ),( Keisuke Ando ),( Nobuaki Hattori ) 한국목재공학회 2004 한국목재공학회 학술발표논문집 Vol.2004 No.-

Characteristics of White Charcoal Produced from the Charcoal Kiln for Thermotherapy(온열욕 겸용 숯가마에서 생산된 백탄의 특성)

( Gu Joong Kwon ),( Ah Ran Kim ),( Hee Soo Lee ),( Seung Hwan Lee ),( Wahyu Hidayat ),( Fauzi Febrianto ),( Nam Hun Kim ) 한국목재공학회 2018 목재공학 Vol.46 No.5

In this study, the characteristics of the white charcoal from charcoal kilns made for both charcoal production and thermotherapy and from the traditional charcoal kiln were compared and examined. A charcoal kiln for thermotherapy as a secondary purpose was made to minimize environmental problems such as fine dust and harmful gas generated from sealed charcoal kiln in consideration of comfort and safety. White Charcoal produced from the charcoal kiln for both charcoal production and thermotherapy had higher ash and volatile matter and lower fixed carbon than that from the traditional charcoal kiln. The density of the white charcoal produced from the charcoal kiln for both charcoal production and thermotherapy was slightly higher than that of the traditional one, but the equilibrium moisture content and pH were not significantly different. The calorific value, refinement degree, hardness and anatomical structure were not different between the two. It was concluded that the white charcoal produced from the advanced charcoal kiln for thermotherapy as a secondary purpose meets the quality certification standards of Korea Forest Research Institute.

Effect of temperature on chemical composition change of Quercus mongolica wood using deep eutectic solvents

Gu-Joong Kwon,Chan-Woo Park,Song-Yi Han,Ji-Soo Park,Eun-Ah Lee,Nam-Hun Kim,Seung-Hwan Lee 강원대학교 산림과학연구소 2019 강원대학교 산림과학연구소 학술대회 Vol.2019 No.09

Deep eutectic solvents (DESs) are nontoxic, low vapor pressure, biodegradable, chemically stable and environmentally friendly solvents. Among the various DES solvents we are interested in DES based on choline chloride. Choline chloride acts as a hydrogen bond acceptor (HBA) and combines with other hydrogen bond donors (HBD) such as urea, carboxylic acids, sugars or alcohols to form a low melting eutectic mixture. It affects the physical and chemical properties of DES, such as its melting point. Therefore, in this study, the effects of treatment temperature on the chemical composition change of Quercus mongolica wood by choline chloride based eutectic solvent (1: 2 molar ratio) were investigated. The deep eutectic solvent pretreatment temperature was carried out at 100℃ and 140℃. The yield by all DES treatments decreases with increasing processing time. ChCl/lactic acid showed the lowest yield compared to other DESs. ChCl/urea and ChCl/glycerin showed similar characteristics. The chemical composition of the ChCl/lactic acid eutectic solvent decreased with increasing treatment time, but increased with increasing treatment time at 140℃. ChCl/urea and ChCl/glycerin showed little change of lignin and change of cellulose and hemicellulose at 140℃. The crystallinity of cellulose was slightly higher than that of other eutectic solvents, but it was not affected by the treatment temperature.

Cellulose nanofibrils prepared by deep eutectic solvent treatment

Gu-Joong Kwon,Chan-Woo Park,Song-Yi Han,Ji-Soo Park,Eun-Ah Lee,Nam-Hun Kim,Seung-Hwan Lee 강원대학교 산림과학연구소 2019 강원대학교 산림과학연구소 학술대회 Vol.2019 No.09

Deep eutectic solvent (DES) can be considered a next-generation ionic solvent consisting of a mixture of two or more compounds, one of which is a salt. The formation of new liquid compounds at room temperature is due to the formation of hydrogen bonds between the hydrogen bond donor (HBD) and the hydrogen bond acceptor (HBA), generally the halide anions present in the salt. This DES is a fairly new kind of green solvent that can be applied to various fields, and attracts much attention as an alternative to IL. This study examines the choline chloride-based DES treatment as a new pretreatment for the production of cellulose nanofibers. In the Experiments, deep eutectic solvent systems having lactic acid, urea and glycerin as the second component were formed at 100 °C and then applied to decompose wood-derived cellulose fibers. DES-pretreated fibers were nanofibrillated by mechanical treatment using a blender and their properties were analyzed. Cellulose nanofibrils with a width of 4.7 to 5.4 nm were successfully produced from DES pretreatment under all conditions. As a result, choline chloride-based DES has shown high potential as an environmentally friendly solvent in the production of cellulose nanofibrils.

홀로셀룰로오스 에어로겔의 특성

권구중 ( Gu Joong Kwon ),김대영 ( Dae Young Kim ),김남훈 ( Nam Hun Kim ) 한국목재공학회 2010 목재공학 Vol.38 No.3

This study was carried out to investigate the characterization of aerogel made by holocellulose, the thermal properties of the aerogel, and its shapes and porous structures. The aerogel was made by holocellulose through the gelation in alkali hydroxide-urea solution and freeze drying processes. Holocellulose aerogel had porous structure such as net or sponge. The density of holocellulose aerogel was 0.04 g/cm3, and the specific surface area 145.3 m2/g. Although thermal degradation occurred in the range of 210∼350°C, significant thermal degradation occurred at low temperature with low heating rate, Micropore volume was sharply increased with low heating rate. Holocellulose aerogel char obtained by carbonization with 900°C and 0.5°C/min. heating rate had the highest surface area, 656.7 m2/g. The deformed and irregular structures of holocellulose aerogel chars due to the thermal degradation were observed in SEM.

폐열에너지를 활용한 친환경건조시스템 개발

권구중 ( Gu Joong Kwon ),권성민 ( Sung Min Kwon ),장재혁 ( Jae Hyeok Jang ),황원중 ( Won Joung Hwang ),김남훈 ( Nam Hun Kim ) 한국목재공학회 2011 목재공학 Vol.39 No.6

This study was preformed to investigate the characteristics of the green drying system for utilizing heat wasted during carbonization process. The green drying system utilizing waste heat is one of environment-friendly equipments because it needs no other energies from fossil fuel and etc. In this study, waste heat from three kilns was collected by stainless connection pipe, and in the green drying system the temperature and humidity was hardly changed. Charcoal charecteristics as fixed carbon, refining degree, hardness, pH, calorific value, and charcoal yield were analyzed to investigate kiln performance due to installation of green drying system. As a result, the green dry system installation hardly affected the characteristics of charcoal. In conclusion, the green drying system can be applied to maximize the profit of the farm household income and contribute to reduce fossil energy.