• Journal of Adhesion and Interface
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• v.16 no.2
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• pp.63-68
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• 2015

We synthesized thermoplastic polyurethane elastomer containing carboxylic acid group and TPV (thermoplastic vulcanizate). We measured the mechanical, grip, debris, contact angle and adhesion properties according to introducing acid group in elastomer structure. Mechanical and wet slip properties were improved because of the hydrogen bonding by introduction of acid group. Also adhesion strength was increased as increasing of surface polarity by carboxylic acid group. The debris property of TPV made from TPU containing carboxylic acid group was improved.

• Composites Research
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• v.26 no.5
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• pp.315-321
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• 2013

In this work, pitch-carbonized glass fibers were prepared for reinforcement of composites. The influence of acid functionalization of the fibers on the morphological, mechanical, and thermal properties of fiber-reinforced epoxy matrix composites was investigated. The acid functionalization of the fibers led to 10 and 150% increases in the mechanical and thermal properties, respectively, as compared to carbon fiber-reinforced composites. This can be attributed to the superior orientation of fiber structures and good interfacial interactions between fillers and epoxy matrix, resulting in enhanced degree of dispersion and formation of thermally conductive paths in the functionalized composites.

• Journal of Adhesion and Interface
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• v.9 no.4
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• pp.1-11
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• 2008

In the present study, kenaf fibers were treated with sodium hydroxide using soaking and ultrasonic methods prior to biocomposite processing, respectively. The effect of alkali treatment on the kenaf-PLA interfacial adhesion and mechanical and thermal characteristics of kenaf/poly(lactic acid) biocomposites was investigated in terms of their interfacial shear strength, flexural properties, dynamic mechanical properties and thermal stability and also microscopic observations of kenaf fibers and the composite fracture surfaces. As a result, use of both soaking and ultrasonic methods for treating kenaf fiber surfaces played a role in increasing the fiber-matrix adhesion and the mechanical properties of the biocomposites. Their characteristics depended not only on the fiber surface treatment method but also on the treatment condition like alkali concentration and treatment time.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.8
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• pp.677-682
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• 2015

We simulate an emulsion system under simple shear rates to analyze its rheological characteristics using the lattice Boltzmann method (LBM). We calculate the relative viscosity of an emulsion under a simple shear flow along with changes in temperature, shear rate, and surfactant concentration. The relative viscosity of emulsions decreased with an increase in temperature. We observed the shear-thinning phenomena, which is responsible for the inverse proportion between the shear rate and viscosity. An increase in the interfacial tension caused a decrease in the relative viscosity of the decane-in-water emulsion because the increased deformation caused by the decreased interfacial tension significantly influenced the wall shear stress.

• Polymer(Korea)
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• v.36 no.5
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• pp.573-578
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• 2012

In general, most physical properties of wood/polyvinyl chloride (PVC) composites are lower than those of corresponding neat PVC resin because of poor interfacial adhesion between the hydrophilic wood flour and hydrophobic PVC. Therefore, in this study, we treated wood flour with three aminosilanes to improve wood/PVC interfacial adhesion strength, and eco-friendly wood/PVC/nanoclay composites were prepared by melt blending the aminosilane-treated wood flour, a heavy metal free PVC compound, and a type of nanoclay. The effects of treating wood flour with the aminosilanes and adding the nanoclay on the mechanical properties of the composites were investigated. Mechanical properties of the composites were investigated by universal testing machine (UTM), izod impact tester, dynamic mechanical analyzer (DMA), and thermomechanical analyzer (TMA). The tensile properties of the composites with the aminosilane-treated wood flour were considerably higher than those of the composites with neat wood flour. Furthermore, a small amount of the nanoclay improved mechanical properties of the composites. The performance of the wood/PVC composites was considerably improved by using the aminosilane-treated wood flour and the nanoclay.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.454-455
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• 2007

송전용 자기 애자에 대하여 산물화염 특성과 송전선로의 환경 검토를 토대로 송전용 절연물에 대한 산불화염 열화특성을 1)내열충격 열화와 2) 열충격 싸이클 열화로 나누어 가속시킨 후 절연물의 성능을 시험 평가하였다. 또한 승전용 자기애자 (254mm, 36,000lbs)를 대상으로 실제 삼불열화 조건을 근간으로 기계적, 열적 환경을 고려한 자기애자의의 수축, 팽창 변위에 따른 계면의 응력거동을 열충격 및 내열충격 시험의 결과와 비교 분석하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.3
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• pp.887-897
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• 1991

본 연구에서는 이와 같은 배경에서, Fig. 1(f)와 같이 가장 일반적인 이방성 재료가 접합된 경우의 응력확대계수를 명확히 정의하고, 수치해석법으로 구할 수 있는 외삽식을 제안한다. 또한, 탄성문제의 수치해석 방법으로 적은 요소의 분할로써 고 정밀도의 수치해석 결과를 얻을 수 있는 경계요소법(boundary element method:BEM), 특히 저자들이 개발한 복합재료에 대한 2차원 경계요소법 프로그램을 이용하여 이방성 이종재료 접합계면 균열의 응력확대계수를 해석하고, 복합재료내의 섬유방향에 대한 접합계면 균열의 정성적 거동을 고찰하고자 한다.

• Polymer(Korea)
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• v.26 no.6
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• pp.718-727
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• 2002

In this work, an Ar+ beam was irradiated on carbon fiber surfaces to improve the interfacial shear strength (IFSS) of the resulting composites using an ion assisted reaction (IAR) method h single fiber pull-out test was executed to investigate the basic characteristics of the single Carbon fiber/matrix interface. Based on Greszczuk's geometrical model, the debonding force for pull-out of the fiber from the resins was discussed with the applied ion beam energy as a result, it was known that an ion beam treatment produced the functional groups on fiber surface and etching lines along the fiber axis direction, resulting in increasing the adhesion forces between fibers and matrix, which caused the improvement of the IFSS in a composite system. And, it was also found that the maximum IFSS was shown at 0.8 keV ion beam energy in this system.

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.05a
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• pp.24-24
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• 1996

• Journal of Adhesion and Interface
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• v.17 no.3
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• pp.96-103
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• 2016

In this work, pellets consisting of cellulose-based natural fiber bamboo and poly(lactic acid) (PLA) was prepared by extrusion process and then bamboo fiber/PLA biocomposites with various fiber contents were produced by injection molding process. The water treatment effect of bamboo fibers on the flexural, tensile, and impact properties and heat deflection temperature of the biocomposites were investigated. The thermal stability of bamboo and the flexural properties, tensile modulus, and impact strength depended on the presence and absence of water treatment as well as on the fiber content, whereas the heat deflection temperature are influenced mainly by water treatment. The increase of the mechanical and impact properties of biocomposites is ascribed to the improvement of the interfacial adhesion between the bamboo fibers and the PLA matrix by the water treatment. The result suggests that the pre-treatment of natural fibers by using water, which is environment-friendly and labor-friendly, may contribute to enhancing the performance of biocomposites.