• Journal of the Korean Wood Science and Technology
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• 제40권5호
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• pp.343-351
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• 2012

A large diameter roundwood is an important element of Korean traditional buildings, Hanok, and is hard to be dried without surface cracks. Four different pretreatments, such as pre-cracking, oil heating, kerfing-oil heating and PEG impregnation, were investigated for reducing the surface cracks of large-diameter roundwood specimens during heat treatment. The roundwood specimens of pre-cracking, oil heating and kerfing-oil heating showed surface cracks during pretreatment, but that of PEG impregnation did not. It was confirmed that kerfing reduced the total crack width. Among the four pretreatments and control only the PEG impregnation roundwood specimen had no crack on both outer and inner surfaces after heat treatment. The PEG impregnation specimen shrank only 1.6% in the tangential direction while the pre-cracking did 8.0%.

• 펄프종이기술
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• 제42권3호
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• pp.67-73
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• 2010

Pine (Pinus densiflora) and aspen (Populus euramericana) wood meals were treated with ozone at various time schedule in acidic condition. The lignin contents and surface area of the ozone treated wood meals were determined and the enzymatic hydrolysis rate of ozonated wood meals was evaluated. The feasibility of enzymatic hydrolysis of the ozone treated wood meal was obviously influenced with the degree of delignification. After ozone treatment of wood meal for 10min, total pore volume were slightly increased in the surface of wood meal. When wood meals were treated with ozone longer than 10min, few change in the pore volume was observed. However, the area of over $50{\AA}$ of pore size is increased with ozonation time. As a conclusion, the rate of enzymatic hydrolysis of wood is more effective with the pore size distribution than the total pore volume.

• Composites Research
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• 제30권2호
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• pp.145-148
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• 2017

프로필렌의 플라즈마 처리로 목분을 표면 개질하여 복합재 기지인 PP와 상용성을 가지게 하였다. 프로필렌을 플라즈마로 처리하여 증착된 소수성 박막 필름의 화학적 구조는 PP와 흡사하였다. 목분과 PP는 이축 압출기에 의해 펠렛으로 만들어 졌고 50 wt% wood powder/PP 복합재료는 사출 성형기에 의해 성형되었다. 인장강도와 굴곡 강도는 최고 7.59% and 12.43%까지 향상되었으며 파단면에 대한 SEM 관찰로 플라즈마 중합이 계면 접착력과 기계적 특성을 향상시킨 것을 볼 수 있었다.

• 보존과학회지
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• 제32권2호
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• pp.155-165
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• 2016

수침고목재인 목재유물의 보존처리에 가장 많이 사용되는 PEG 함침 후 진공동결건조 방법의 단점인 표면 결함에 대한 안정화처리를 위해 HPC를 도포하였다. HPC의 효과를 확인하기 위해서 외관 및 실체현미경 관찰, 색차, 중량변화율, 치수변화율을 측정하고, 통계분석을 실시하였다. 목재시료의 표면에 HPC가 얇은 층을 형성하였고, 가도관의 관공과 균열의 틈 사이를 메우고 있었다. HPC 1,000,000을 처리한 시료의 부후되지 않은 표면에서 나타난 백화현상을 제외하고 다른 변화는 나타나지 않았다. 열화시킨 시료는 수분 흡착에 의한 색변화가 나타났다. 시료 표면의 얇은 HPC 층은 열화 후에도 유지되고 있었으며, 수분 흡착에 의한 중량변화와 치수변화는 HPC에 의해 억제되는 것으로 나타났다.

• 자원리싸이클링
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• 제22권2호
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• pp.18-21
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• 2013

본 실험에서는 상압플라즈마에 의한 목분의 표면개질에 대해 조사하였다. 복합재는 목분과 폴리프로필렌을 이용하여 제작되었다(목분 : 폴리프로필렌=55wt% : 45wt%). 상압플라즈마는 carrier gas로 헬륨과 HMDSO를 모노머로 사용하였고 3 KV, $17{\pm}1$KHz, 2 g/min의 조건에서 처리하였다. 폐목분의 인장강도는 상압플라즈마 처리를 통해 18.5 MPa에서 21.2 MPa로 14.6% 증가하였고 단일수종목분의 경우에도 21.5 MPa에서 23.4 MPa로 8.8% 증가하였다. 이것으로 상압플라즈마 처리는 목분의 표면을 개질하여 폴리프로필렌과의 계면결합력을 증가시켜주는 것을 확인하였다.

• Journal of the Korean Wood Science and Technology
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• 제23권1호
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• pp.54-60
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• 1995

This paper reports on the changes of equilibrium moisture contents and specific surface areas of Poplar wood(Populus euramericana) for various steam explosion treatments. Equilibrium moisture contents(EMC) and specific surfaces of steam exploded woods were measured under the moisture adsorption course at 25$^{\circ}C$, and compared with those of other materials and wood meals. The EMCs of steam exploded wood meal were 1~5% less in comparison with that of wood meal. In the case of delignified steam exploded wood meal and delignified wood meal, the same tendency was appeared too. But absolute values of EMCs for delignified wood meals were larger than those of the wood meal. For the changes of EMC by the steam exploded conditions, the EMC decreased with the increase of the steam explosion pressure. On the other hand, specific surface areas were calculated from BET plots based on amounts of monomolecular vapor adsorption of various wood meals. Specific surface areas of the wood meal and delignified wood meal were 90~145, 34~90($m^2/g$) respectively, and which were greater in comparison with those of steam exploded wood meals and delignified steam exploded wood meals. From these results, it is considered that the amount of water vapor adsorption was decreased by the increase of the crystallinity, effect of heat treatment, and coating by melted lignin in during the steam explosion.

• Journal of the Korean Wood Science and Technology
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• 제40권6호
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• pp.370-377
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• 2012

잣나무(Pinus koraiensis S. et Z.)와 로지폴소나무(Pinus contorta Dougl)를 이용하여 열처리 목재를 제조한 후 처리조건에 따른 재색변화를 조사하였다. 반응표면분석법에 따라 설정된 9가지 처리조건(처리온도 : 170, 180, 200, 220, $230^{\circ}C$, 처리시간: 90, 120, 180, 240, 270 min.)에서 열처리 시편들을 제조하였으며, 색차계를 이용하여 재색을 측정한 후 흰개미 저항성을 평가하기 위하여 진주에 설치된 흰개미 시험장에서 6개월 동안 야외노출시험을 실시하였다. 처리온도와 처리시간이 증가함에 따라 명도가 감소하였으며 감소폭은 시간보다 온도에 의한 영향이 더 큰 것으로 나타났다. 미국국립표준국(National Bureau of Standards : NBS)에서 제시된 방식에 의해 평가된 색차를 처리온도와 처리시간의 함수로 표현한 반응표면분석모델은 잣나무의 경우 $R^2$의 값이 0.92, 로지폴파인의 경우 0.88로 열처리조건에 따른 색채의 예측가능성을 보여주었다. 6개월의 야외시험결과 열처리 조건에 상관없이 흰개미 가해가 심하게 발생된 것으로 나타났는데, 이는 제조된 열처리 목재의 흰개미 저항성이 야외에 사용하기에 적합하지 않다는 것을 보여준다.

• Journal of the Korean Wood Science and Technology
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• 제39권2호
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• pp.125-131
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• 2011

The characteristics of radio-frequency/vacuum drying Japanese larch boxed heart round logs with 150 mm and 210 mm in diameter and 2,500 mm in length, subjected to compressive loading, after the pretreatment of kerf were investigated. The results of this study were as the follows: The drying time of about 120 hours~130 hours was needed from green to about 15 percent of moisture content. The gradient of final moisture content for all specimens was very gentle in both longitudinal and transverse directions owing to dielectric heating. The surface checks seriously occurred although the occurrence extent of surface check for the kerfed specimens was slight compared with that for the control specimens because drying stress was relieved by kerf. The occurrence of surface checks for the L-specimen was more serious than that for the S-specimen.

• Journal of the Korean Wood Science and Technology
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• 제51권6호
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• pp.493-508
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• 2023

Round timber materials of 600 mm length, cut from large-cross-section round timber of red pine (Pinus densiflora S. et Z.) of 450 mm width and 4.2 m length, were prepared as the target of kiln drying in this study. After treating the target materials through end sealing (ES), end sealing - kerfing (ES-K), lateral sealing - end sealing - boring (LS-ES-B), or lateral sealing - partial end sealing (LS-PES), the effects of the treatment on the incidence of drying defects were determined. The target materials with exposed lateral surface and sealed cross surface were steamed at the initial temperature of 65℃ above the official pest control temperature of 56℃, followed by kiln drying toward the final temperature of 75℃. The target materials with sealed lateral surfaces, on the other hand, were dried at the initial temperature of 90℃ at almost the maximum temperature of conventional kiln drying, as there is no risk of early check formation caused by surface moisture evaporation. The final temperature was set at approximately 100℃. The drying time, taken for the target materials with initial moisture content of 70%-80% to reach the target moisture content of 19%, varied across treatment conditions. The measured drying time was 1,146 hours (approximately 48 days) for the timber with sealed cross surface and 745 hours (approximately 31 days) for the timber with sealed lateral surface, until the moisture content reached the target level. The formation of surface checks could not be prevented in the control and ES groups, but a definite preventive effect was obtained for the LS-ES-B and LS-PES groups.

• Journal of the Korean Wood Science and Technology
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• 제33권4호통권132호
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• pp.9-14
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• 2005

목재에 대한 탈리그닌처리에 의한 목재의 흡음성능과 구조적 특징의 변화를 관찰하고자 목재횡단방향으로 채취한 원반형시험편을 탈리그닌처리하여 무 처리 목재와 구조적 특징의 변화를 관찰하고, 흡음율을 측정 비교하였다. 측정주파수범위에서 탈리그닌처리한 시험편이 보통의 시험편보다 높은 흡음율을 나타내었으며, 특히 2~4 KHz의 주파수영역에서는 50% 정도 높은 흡음율을 나타내었다. 또한 탈리그닌처리한 목재는 무 처리 목재보다 중량이 8% 정도 감소하였으며, 탈리그닌처리한 목재의 횡단면에서는 다수의 미세할렬이 발생하여 이들이 흡음공극으로 작용하여 특정주파수영역에서 흡음율이 증가된 것으로 사료된다.