• 폴리머
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• 제39권2호
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• pp.256-260
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• 2015

우레탄 아크릴레이트에 montmorillonite(MMT)를 첨가한 UV 경화형 나노복합체 제조 시 사용하는 광개시제의 종류에 따른 기계적 성질 및 내흡수성을 조사하였다. 1 wt%의 MMT가 첨가될 경우 가장 우수한 인장강도와 내흡수성을 나타내었으며, 광개시제의 경우 기존의 benzyldimethylketal 계열 광개시제와 bisacyl phosphine oxide 계열의 광개시제를 함께 사용할 경우 3 wt%의 MMT 함량에서도 사용된 UV 램프의 방출 파장대인 340~450 nm에서의 광흡수가 강화되어 나노복합체의 경화거동에 보다 효과적인 것으로 확인되었다.

• 한국세라믹학회지
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• 제32권11호
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• pp.1219-1226
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• 1995

Creep behaviors of Cr3C2 composites containing 90 wt% Cr3C2 and 10 wt% Ni were studied at high temperature. Compression tests at 100$0^{\circ}C$ and bending tests at 100$0^{\circ}C$ and 105$0^{\circ}C$ were done in argon environment. In all test conditions primary and steady-state creep behaviors were observed. Stress exponent and activatiion energy were determined from the experimental data. By microstructural analysis of Cr3C2 composites after creep test, the separate agglomerations of Ni phase were observed. Numerical analysis was also studied to analyze bending creep behaviors of Cr3C2 by assumming different tensile and compressive creep behavior in a bending sample. From the analysis, it was found that the stress state at the compressive region as applied stress increased. The observed creep rates were compared with the predicted creep rates by estimating power-law creep parameters from bending test data.

• 한국해양공학회지
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• 제15권3호
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• pp.69-74
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• 2001

This paper was to investigate of a adhesiveness for the plasma sprayed coating materials did salt spray by acoustic emission method in tensile loadings. The powders used for the coating were nickel aluminum composite powder Ni-4.5wt.%Al and titanium dioxide powder $TiO_2$. These powders were coated on a carbon steel S45C by plasma spray method. The result solution was a 5% NaCl and the slat spray times were 2, 5 and 10 hours respectively. The salt solution penetrated into the surface of the substrate through pore of the coating layer built in the process of plasma spay. Corrosion productions formed on the surface of substrate. The adhesiveness between the substrate and the coating layer is weaken by corrosion and the exfoliation initiated chiefly at the corrosion surface of the substrate. The AE events and energy of the corroded coating specimens decreased as the salt spray times increased.

• 패션비즈니스
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• 제8권1호
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• pp.156-163
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• 2004

The purpose of this study is to investigate the change of handle when cotton fabric is treated with chitosan-polyurethane mixed solution and crosslinked with epichlorohydrin in order to form three-dimensional crosslinks in the molecules, which in turn would improve the wash-fastness of the chitosan-treated fabrics. The application of epichlorohydrin decreased the EM(Tensile extensibility) and WT(Tensile energy) values, indicating the stiffness increased in the treated fabrics due to the 3-dimensional crosslinking. The crosslinking of the cotton fabric samples resulted in the increase in T.H.V. effectively for the use of summer dress shirt fabric.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.344-349
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• 2001

This paper was to investigate of a adhesiveness for the plasma sprayed coating materials did salt spray by acoustic emission method in tensile loadings. The powders used for the coating were nickel aluminum composite powder Ni-4,5wt.%Al and titanium dioxide powder Ti02. These powders were coated on a carbon steel S45C by plasma spray method. The salt solution was a 5% NaCl and the salt spray times were 2, 5 and 10 hours respectively. The salt solution penetrated into the surface of the substrate through pore of the coating layer built in the process of plasma spay. Corrosion productions formed on the surface of substrate. The adhesiveness between the substrate and the coating layer is weaken by corrosion and the exfoliation initiated chiefly at the corrosion surface of the substrate. The AE events and energy of the corroded coating specimens decreased as the salt spray times increased.

• 멤브레인
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• 제22권3호
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• pp.208-215
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• 2012

PVA와 PAA블랜드의 용액주조법을 통하여 겔 고분자 전해질막이 제조되었다. 블랜드 내의 PAA함량은 30에서 80 wt% 사이 범위에서 조절되었다. 겔 고분자 전해질을 이용하여 아연공기전지를 제작하였다. 제조된 겔 고분자 전해질의 기계적, 전기적 특성을 인장실험과 임피던스 실험을 통하여 측정하였다. 아연공기전지의 성능은 current interrupt method와 정전류 방전실험을 통하여 측정하였다. 겔 고분자 전해질 내의 PAA함량이 증가함에 따라 인장강도 및 인장탄성계수가 감소하였다. 반면, PAA함량의 증가에 따라 겔 고분자 전해질막의 이온전도도는 증가하였다. 이와 같은 이온전도도의 증가의 아연공기전지 내에서의 효과는 current interrupt method와 정전류 방전실험에서 확인되었다. PAA함량이 높은 겔 전해질막으로 제조된 전지는 낮은 IR손실과 높은 방전용량을 보였다.

• Advances in nano research
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• 제13권1호
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• pp.97-111
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• 2022

In the present article, silica nanoparticles (SNPs) were exploited to improve the tribological and mechanical properties of vinyl ester/glass fiber composites. To the best of our knowledge, there hasn't been any prior study on the wear properties of glass fiber reinforced vinyl ester SiO₂ nanocomposites. The wear resistance is a critical concern in many industries which needs to be managed effectively to reduce high costs. To examine the influence of SNPs on the mechanical properties, seven different weight percentages of vinyl ester/nano-silica composites were initially fabricated. Afterward, based on the tensile testing results of the silica nanocomposites, four wt% of SNPs were selected to fabricate a ternary composite composed of vinyl ester/glass fiber/nano-silica using vacuum-assisted resin transfer molding. At the next stage, the tensile, three-point flexural, Charpy impact, and pin-on-disk wear tests were performed on the ternary composites. The fractured surfaces were analyzed by scanning electron microscopy (SEM) images after conducting previous tests. The most important and interesting result of this study was the development of a nanocomposite that exhibited a 52.2% decrease in the mean coefficient of friction (COF) by augmenting the SNPs, which is beneficial for the fabrication/repair of composite/steel energy pipelines as well as hydraulic and pneumatic pipe systems conveying abrasive materials. Moreover, the weight loss due to wearing the ternary composite containing one wt% of SNPs was significantly reduced by 70%. Such enhanced property of the fabricated nanocomposite may also be an important design factor for marine structures, bridges, and transportation of wind turbine blades.

• Korean Chemical Engineering Research
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• 제50권1호
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• pp.6-10
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• 2012

본 연구의 목적은 styrene-butadiene-styrene(SBS) 블록공중합체와 폐타이어 고무분말(crumb rubber, CR)로 개질한 아스팔트의 저온접착특성에 대해 파라핀오일 가소제의 영향에 대한 것이다. SBS/CR로 개질한 아스팔트 블렌드와 파라핀오일/SBS/CR 아스팔트 블렌드의 온도 민감성을 침입도와 연화점으로 측정하였다. 형광현미경으로 파라핀오일/SBS/CR 아스팔트 블렌드에 대한 개질제들의 분산 상태와 만능시험기로 저온에서 접착성질을 각각 측정하였다. 저온접착시험에서 SBS 함량의 증가와 파라핀오일 함량 5 wt % 및 10 wt %에서 접착강도와 변형률이 증가하였다. $-20^{\circ}C$에서 측정한 접착강도와 강인성은 파라핀오일이 10 wt %와 SBS 공중합체의 양이 6 wt %인 조성에서 최대값을 얻었다. SBS/CR/아스팔트 블렌드에서 파라핀오일의 첨가는 유연성을 부여하는 효과를 나타내고, 저온에서 강인성의 증가를 가져오는 것을 확인하였다.

• 한국의류산업학회지
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• 제3권5호
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• pp.466-472
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• 2001

To find a suitable condition in this process examined, we investigated the main control factors, such as, the NaOH concentrations, such as, the NaOH concentrations, the heat treating times, and the heating temperatures. The resulting mechanical properties of the fabrics also studied. The samples used were Nylon/Co-PET sea-island type composite microfiber (Co-PET content: 35%) non-woven fabric. The conclusions obtained were as follows. 1. For the complete extraction of Co-PET from the sample non-woven fabric in the dry hot air process, $160^{\circ}C$ of air temperature, 15 min. of treatment time, and around 30% of NaOH concentration were required. On the other hand, in the wet hot air process, $140^{\circ}C$ of air temperature, 3.5 min. of treatment time, and around 30% of NaOH concentration were required. 2. The mechanical properties of the continuous processed samples showed that the WT, B, and WC increased with increasing the weight reduction ratio. However, the G, decreased with increasing the weight loss ratio. Note that, particularly in B, it increased drastically when the weight deduction ratios exceeded 30%. 3. As increasing the wet hot air temperature from 130 to $140^{\circ}C$, B appeared to increase, however, WT, G, and WC appeared to decrease. 4. The best condition found in this continuous process to extract Co-PET is the wet hot air temperature of 140, NaOH concentration of 28% or above, and the treatment time 2-4 min.

• 한국염색가공학회지
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• 제30권1호
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• pp.9-19
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• 2018

To prepare bio-inspired antifouling coating materials having similar structure with lotus, self-crosslinkable waterborne polyurethanes emulsions containing paraffin wax (CWPU/P0, 0.25, 0.5, 1.0, 1.5, 2.0, the number indicated the wt% of wax) were prepared by an emulsifier-free/solvent free prepolymer mixing process. The as-polymerized CWPU/P emulsions containing 0 - 1.00wt% of paraffin wax were found to be stable after 4 months, however, CWPU/P emulsions containing 1.50 and 2.00wt% of paraffin wax were unstable within 1 month storage. Considering the stability of emulsions, the optimum paraffin wax content was found to be about 1wt% to obtain stable antifouling coating emulsion material. The surface topology of CWPU/P film samples was characterized by atomic force microscopy (AFM). This study examined the effect of paraffin wax content on the surface roughness, water contact angle/surface energy, water swelling, light transmittance and tensile properties of CWPU/P film samples.