• Journal of the Korean Wood Science and Technology
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• 제50권3호
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• pp.167-178
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• 2022

To investigate the influence of manufacturing environment on bonding performance of mixed cross laminated wood (CLT) using polyurethane (PUR) adhesive, a boiling water soak delamination test according to the temperature and relative humidity was conducted. The 5-ply mixed CLT consisted of Japanese Larch for external and middle layer and yellow poplar for internal layer. The PUR adhesives with different opening times of 10 and 30 minutes were used. The mixed CLT was manufactured according to pressing times of PUR and manufacturing environments of summer and winter. In case of summer environment, the delamination rate of the mixed CLT with pressing time of 4 hours using a PUR adhesive with open time of 10 minutes met the requirements of KS F 2081. In case of winter environment, the delamination rate of the mixed CLT didn't meet the requirements of KS standard. However, it was possible to confirm the effect of improving the adhesive performance by adjusting the pressing time according to the open time of the adhesive under the manufacturing conditions. The delamination rate of CLT with open time 30 minutes PUR, manufactured by indirect moisture supply methods was 11.2% better than direct moisture supply methods. As a result of delamination test in the same condition of relative humidity and adhesive, it was found that the temperature of manufacturing environment influences the adhesive performance.

• 펄프종이기술
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• 제46권4호
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• pp.44-53
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• 2014

This research were aimed at developing starches which have high preservability and high bonding strength from corn starch, modified cationic and oxidized corn starches, as compared to the fermented wheat starch. On the lining that attaching the base paper on the back of the work with paste, the coating weight was determined by the solid contents of the paste rather than the viscosity of paste. Adhesive strength and stiffness were also determined by the solid contents of the paste. Corn starch had lower solid contents, higher viscosity, and higher adhesive strength than other starches. In the iodine stain to the surface of peeled base paper off, paste deeply penetrated into the traditional Hanji than modern Hanji. And oxidized starch paste deeply penetrated into the paper layer than the cationic starch.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.111-115
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• 2005

Recently, natural fibers draw much interests in composite industry due to low cost, light weight, and environment-friendly characteristics compared with glass fibers. In this study, mechanical properties were evaluated for two extreme cases of jute fiber orientations, i.e. the unidirectional yarn composites and the felt fabric composites. Samples of jute fiber composites were fabricated by RTM process using epoxy resin, and tensile, compression, and shear tests were conducted. As can be expected, unidirectional fiber specimens in longitudinal direction showed the highest strength and modulus. Compared with glass/epoxy composites of the similar fabric architecture and fiber volume fraction, the tensile strength and modulus of jute felt/epoxy composites reached only 40% and 50% levels. However, the specific tensile strength and modulus increased to 80% and 90% of the glass/epoxy composites. The main reason for the poor mechanical properties of jute composites is associated with the weak interfacial bonding between fiber and matrix. The effect of surface treatment of jute fibers on the interfacial bonding will be examined in the future work.

• 펄프종이기술
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• 제43권4호
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• pp.31-39
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• 2011

One of the main drawbacks of wood fibers based composite materials are their tendency to swell due to moisture uptake in wet and moist environments. The main contribution to the hygroexpansion usually comes from the hydrophilic wood fibers. Recent trend toward the high speed printing, copying, and precision converting precesses demands a high level of dimensional stability under various environmental conditions. The purpose of this study was to investigate the dimensional stability of softwood bleached kraft pulp handsheets depending on wet pressing conditions. By increasing the number of wet pressing, dimensional stability was decreased because of increased fiber-to-fiber bonding. Hygroexpansion of handsheets had a linear relationship with the relative bonded area and equilibrium moisture contents. Dip elongation was decreased when the number of wet pressing was increased because of increased fiber-to-fiber bonding to resist low load in water.

• 대한가정학회지
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• 제44권12호
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• pp.31-42
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• 2006

The purpose of this study was to investigate the correlation among parental bonding, attachment styles, love styles and satisfaction in dating and their effects on other variables. The main findings of the study were as follows 1)The stronger the relationship with one's parents in infancy, the higher the possibility to forge secure attachment. 2)There was a significant correlation between attachment styles and love styles. 3)There was a significant correlation between attachment styles and dating satisfaction. 4)There were meaningful differences on dating satisfaction and duration among different love types. This study showed the importance of forging secure attachment between parents and children, and found related variables that can affect dating satisfaction and duration. However, the study results were based on a limited group of people, which limits the generalizability of the results to the general public. Follow-up studies that cover a wide range of age groups and related variables are necessary.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.205.2-205.2
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• 2014

The effects of ion beam mixing of a SiC film coated on super alloys (hastelloy X substrates) were studied, aiming at developing highly sustainable materials at above $900^{\circ}C$ in decomposed sulfuric acid gas (SO2/SO3/H2O) channels of a process heat exchanger. The bonding between two dissimilar materials is often problematic, particularly in coating metals with a ceramics protective layer. A strong bonding between SiC and hastelloy X was achieved by mixing the atoms at the interface by an ion-beam: The film was not peeled-off at ${\geq}900^{\circ}C$, confirming excellent adhesion, although the thermal expansion coefficient of hastelloy X is about three times higher than that of SiC. Instead, the SiC film was cracked along the grain boundary of the substrate at above $700^{\circ}C$. At ${\geq}900^{\circ}C$, the film was crystallized forming islands on the substrate so that a considerable part of the substrate surface could be exposed to the corrosive environment. To cover the exposed areas and cracks multiple coating/IBM processes have been developed. An immersion corrosion test in 80% sulfuric acid at $300^{\circ}C$ for 100 h showed that the weight retain rate was gradually increased when increasing the processing time.

• 농업과학연구
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• 제37권2호
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• pp.267-270
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• 2010

This study was carried out to manufacture black charcoal board from domestic wood waste by using serum protein adhesive which is natural, environment-friendly and human-friendly. For the preparation of the serum protein adhesive, pig blood from slaughterhouse was centrifuged and serum was separated from corpuscles and concentrated to 30% by dry weight basis. The particle size of charcoal from domestic wood waste for this study was #6-60. Hot pressing schedule was $170^{\circ}C$ and 40kgf/$cm^2$ (1 min)-10kgf/$cm^2$ (2.5 min)-40kgf/$cm^2$ (5 min). The black charcoal board made by the addition of 13% serum protein adhesive on dry weight basis gave 41.76kgf/$cm^2$ of bending strength, 8.12kgf/$cm^2$ of internal bonding strength, and excellent gas adsorption and workability.

• 폴리머
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• 제25권5호
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• pp.649-656
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• 2001

비닐아세테이트-비닐알핀을 (VAc-VAL) 공중합체의 조성에 따른 폴리(4-비닐피리딘)(P4VP)/VAc-VAL 공중합체 블렌드의 상용성을 조사하였다. 블렌드 시료의 시차 주사 열분석(DSC0 및 광학현미경에 의한 상분리온도 조사(TOM)를 통하여 P4VP는 VAL의 조성이 30 mole% 이상 함유된 VAc-VAL 공중합체들과 상용성이 있음이 확인되었다. 상용성 P4VP/Vac-VAL 공중합체 블렌드의 푸리에 변환 적외선(FT-IR) 분광 분석 결과 비닐피리딘과 비닐알코올 히드록실기 상에 강한 분자간 수소결합이 형성됨을 확인하였다. 성분 고분자 사이에 분자간 수소결합에 의해서 고분자 블렌드의 상용성이 유도되는 고분자 블렌드계의 열역학적 모델인 Association 모델을 이용하여 P4VP/VAc-VAL 공중합체 블렌드의 이론적인 상 그림을 구하였다. 이론적으로 계산된 binodal 곡선을 실험적으로 구한 흐림점 생성 곡서과 잘 일치하는 결과를 보였다.

• 한국수소및신에너지학회논문집
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• 제27권4호
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• pp.378-385
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• 2016

In this study, we synthesized a biocatalyst consisting of glucose oxidase (GOx), polyethyleneimine (PEI) and carbon nanotube (CNT) with addition of glutaraldehyde (GA)(GA/[GOx/PEI/CNT])for fabrication of glucose sensor. Main bonding of the GA/[GOx/PEI/CNT] catalyst was formed by crosslinking of functional end groups between GOx/PEI and GA. Catalytic activity of GA/[GOx/PEI/CNT] was quantified by UV-Vis and electrochemical measurements. As a result of that, high immobilization ratio of 199% than other catalyst (with only physical adsorption) and large sensitivity value of $13.4{\mu}A/cm^2/mM$ was gained. With estimation of the biosensor stability, it was found that the GA/[GOx/PEI/CNT] kept about 88% of its initial activity even after three weeks. It shows GA minimized the loss of GOx and improved sensing ability and stability compared with that using other biocatalysts.

• 방사선산업학회지
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• 제6권2호
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• pp.125-128
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• 2012

Kenaf (Hibiscuc cannabinus L.) is a renewable resource for industry and kenaf lignin is syringyl-guaiacyl lignin. The electron beam irradiated on kenaf core various doses range from 200 to 1,000 kGy to improve delignification. The yield of lignin, which is 2.53 g from 10 g of electron beam irradiated kenaf core. A comparison extracted lignin between from native kenaf core and electron beam irradiated kenaf core was then studied through chemical structure and bonding property by a Fourier transform infrared spectroscopy (FT-IR). Thermal stability of the extracted-purified lignin was performed via differential scanning calorimetry (DSC). These results were explained that electron beam irradiation increased performance of extracting efficiency.