• Title, Summary, Keyword: carbon nanofiber

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A Study on Mechanical Properties of Carbon Nanofiber/Epoxy Composites with Dispersion Methods (분산 방법에 따른 탄소나노섬유/에폭시 복합재료의 기계적 물성에 관한 연구)

  • Kong Jin-Woo;Chung Sang-Su;Kim Tae-Wook
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.151-154
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    • 2004
  • Despite of the excellent properties of carbon nanofiber, The properties of carbon nanofiber filled polymer composites were not increased largely. The reason is that it is still difficult to ensure the uniform dispersion of carbon nanofiber in a polymer matrix. In this study, For improvement properties of carbon nanofiber filled epoxy composites, the effect of dispersion was investigated. The compounds were prepared by two methods, solution blending and mechanical mixing. Mixing of solution blending method was used using ultrasonic. Dispersion of carbon nanofiber was observed by optical microscope and scanning electron microscope (SEM). UV adsorption and turbidity measured by UV spectrometer was used for the comparison of dispersion of carbon nanofiber.

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Manufacture and Mechanical Properties of Carbon Nanofiber Reinforced Hybrid Composites (탄소나노섬유가 강화된 하이브리드 복합재료의 제조 및 기계적 특성)

  • Chung Sang-Su;Park Ji-Sang;Kim Tae-Wook;Kong Jin-Woo
    • Composites Research
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    • v.18 no.3
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    • pp.1-6
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    • 2005
  • Carbon nanofiber exhibits superior and of ien unique characteristics of mechanical, electrical, chemical and thermal properties. Despite of the excellent properties of carbon nanofiber, the properties of carbon nanofiber filled polymer composites were not increased largely. The reason is that it is still difficult to ensure the uniform dispersion of carbon nanofiber in a polymer matrix. In this study, for improvement of the mechanical properties of composites, carbon nanofiber reinforced hybrid composites was investigated. For the dispersion of carbon nanofiber. solution blending method using ultrasonic was used. Dispersion of carbon nanoifiber was observed by scanning electron microscope (SEH). Mechanical properties were measured by universal testing machine(UTM).

Preparation and Characterization of Carbon Nanofiber Composite Coated Fabric-Heating Elements (탄소나노섬유복합체를 이용한 의류용 직물발열체의 제조 및 특성)

  • Kang, Hyunsuk;Lee, Sunhee
    • Journal of the Korean Society of Clothing and Textiles
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    • v.39 no.2
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    • pp.247-256
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    • 2015
  • This study prepared fabric-heating elements of carbon nanofiber composite to characterize morphologies and electrical properties. Carbon nanofiber composite was prepared with 15wt% PVDF-HFP/acetone solution, and 0, 1, 2, 4, 8, and 16wt% carbon nanofiber. Dispersion of solution was conducted with stirring for a week, sonification for 24 hours, and storage for a month, until coating. Carbon nanofiber composite coated fabrics were prepared by knife-edge coating on nylon fabrics with a thickness of 0.1mm. The morphologies of carbon nanofiber composite coated fabrics were measured by FE-SEM. Surface resistance was determined by KS K0555 and worksurface tester. A heating-pad clamping device connected to a variable AC/DC power supply was used for the electric heating characteristics of the samples and multi-layer fabrics. An infrared camera applied voltages to samples while maintaining a certain distance from fabric surfaces. The results of morphologies indicated that the CNF content increased specifically to the visibility and presence of carbon nanofiber. The surface resistance test results revealed that an increased CNF content improved the performance of coated fabrics. The results of electric heating properties, surface temperatures and current of 16wt% carbon nanofiber composite coated fabrics were $80^{\circ}C$ and 0.35A in the application of a 20V current. Carbon nanofiber composite coated fabrics have excellent electrical characteristics as fabric-heating elements.

Preparation and Characterization of Silicon Carbide Nanofiber (탄화규소 나노섬유의 제조 및 물성)

  • 신현익;송현종;김명수;임연수;이재춘
    • Journal of the Korean Ceramic Society
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    • v.37 no.4
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    • pp.376-380
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    • 2000
  • Carbon nanofibers with an average diameter of 100nm were reacted with SiO vapor generated from a mixture of Si and SiO2 to produce silicon carbide nanofibers at temperature ranging 1200∼1500$^{\circ}C$ under vacuum. The nanofiber reacted at 1200$^{\circ}C$ for two hours consisted of silicon carbide with an average crystallite size of 10-20nm, amorphous silica and a significant amount of unreacted carbon. The surface area of silicon carbide nanofiber, obtained after removal of amorphous silica and unreacted carbon from converted carbon nanofibers at 1200$^{\circ}C$, was as high as 150㎡/g. With increasing reaction temperature to 1500$^{\circ}C$, the surface area was decreased to 14㎡/g. Growth of SiC crystallite size with increasing conversion temperature of carbon nanofiber was confirmed from Scherrer formula using the (111) diffraction line and TEM images of converted carbon nanofibers.

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The study of drawing on the heterogeneous materials for the unidirectional alignment of carbon nanofiber in metal matrix nanocomposite (금속기지 나노복합재용 탄소나노섬유 일방향 배열을 위한 이종재 인발 연구)

  • 백영민;이상관;엄문광;김병민
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.301-301
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    • 2003
  • In current study, Nanocomposites are reinforced with carbon nanofiber, carbon nanotube and SiC, etc. Since the nano reinforcements have the excellent mechanical, thermal and electrical properties compared with that of existing composites, it has lately attracted considerable attention in the various areas. Cu have been widely used as signal transmission materials for electrical electronic components owing to its high electrical conductivity. However, it's size have been limited to small ones due to its poor mechanical properties. Until now, strengthening of the copper alloy was obtained either by the solid solution and precipitation hardening by adding alloy elements or the work hardening by deformation process. Adding the alloy elements lead to reduction of electrical conductivity. In this aspect, if carbon nanofiber is used as reinforcement which have outstanding mechanical strength and electric conductivity, it is possible to develope Cu matrix nanocomposite having almost no loss of electric conductivity. It is expected to be innovative in electric conducting material market. The unidirectional alignment of carbon nanofiber is the most challenging task developing the cooer matrix composites of high strength and electric conductivity. In this study, the unidirectional alignment of carbon nanofibers which is used reinforced material are controlled by drawing process and align mechanism as well as optimized drawing process parameter are verified via numerical analysis. The materials used in this study were pure copper and the nanofibers of 150nm in diameter and of 10∼20$\mu\textrm{m}$ in length. The materials have been tested and the tensile strength was 75MPa with the elongation of 44% for the copper. it is assumed that carbon nanofiber behave like porous elasto-plastic materials. Compaction test was conducted to obtain constitutive properties of carbon nanofiber Optimal parameter for drawing process was obtained by analytical and numerical analysis considering the various drawing angles, reduction areas, friction coefficient, etc. The lower drawing angles and lower reduction areas provides the less rupture of co tube is noticed during the drawing process and the better alignment of carbon nanofiber is obtained.

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Mechanical Properties of Carbon Nanofiber Reinforced Hybrid Composites (탄소나노섬유가 강화된 하이브리드 복합재료의 기계적 물성)

  • Kong Jin-Woo;Chung Sang-Su;Kim Tae-Wook
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.31-34
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    • 2004
  • Carbon nanofiber exhibits superior and often unique characteristics of mechanical, electrical chemical and thermal properties. In this study, For improvement of the mechanical properties of composites, carbon nanofiber reinforced hybrid composites was investigated. For the effect of dispersion, The dispersion methods of solution blending and mechanical mixing were used. The mixing of solution blending method was used using ultrasonic. Dispersion of carbon nanofiber was observed by scanning electron microscope (SEM). Mechanical properties were measured by universal testing Machine (UTM).

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Physical and Mechanical Properties of The Lignin-based Carbon Nanofiber-reinforced Epoxy Composite (에폭시 강화 리그닌 기반 나노탄소섬유 복합재료의 특성)

  • Youe, Won-Jae;Lee, Soo-Min;Lee, Sung-Suk;Kim, Yong Sik
    • Journal of the Korean Wood Science and Technology
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    • v.44 no.3
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    • pp.406-414
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    • 2016
  • The lignin-based carbon nanofiber reinforced epoxy composite has been prepared by immersing carbon nanofiber mat in epoxy resin solution in order to evaluate the physical and mechanical properties. The thermal and mechanical properties of the carbon nanofiber reinforced epoxy composite were analyzed using thermogravimetric analysis (TGA), differential scanning calorimeter (DSC) and tensile tester. It was found that the thermal properties of the carbon nanofiber reinforced epoxy composite improved, with its glass-transition temperature ($T_g$) increased from $90.7^{\circ}C$ ($T_g$ of epoxy resin itself) to $106.9^{\circ}C$. The tensile strengths of carbon nanofiber mats made from both lignin-g-PAN copolymer and PAN were 7.2 MPa and 9.4 MPa, respectively. The resulting tensile strength of lignin-based carbon nanofiber reinforced epoxy composite became 43.0 MPa, the six times higher than that of lignin-based carbon nanofiber mats. The carbon nanofibers were pulled out after the tensile test of the carbon nanofiber reinforced epoxy composite due to high tensile strength (478.8 MPa) of an individual carbon nanofiber itself as well as low interfacial adhesion between fibers and matrices, confirmed by the SEM analysis.

Fabrication and Electrical, Thermal and Morphological Properties of Novel Carbon Nanofiber Web/Unsaturated Polyester Composites

  • Kim, Seong-Hwan;Kwon, Oh-Hyeong;Cho, Dong-Hwan
    • Carbon letters
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    • v.11 no.4
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    • pp.285-292
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    • 2010
  • Novel unsaturated polyester composites with PAN-based nanofiber, stabilized PAN nanofiber, and carbonized nanofiber webs have been fabricated, respectively, and the effects of the nanofiber web content on their electrical resistivity, the thermal stability, dynamic storage modulus, and fracture surfaces were studied. The result demonstrated that the introduction of just one single layer (which is corresponding to 2 wt.%) of the carbonized nanofiber web to unsaturated polyester resin (UPE) could contribute to reducing markedly the electrical resistivity of the resin reflecting the percolation threshold, to improving the storage modulus, and to increasing the thermal stability above $350^{\circ}C$. The effect on decreasing the resistivity and increasing the modulus was the greatest at the carbonized PAN nanofiber web content of 8 wt.%, particularly showing that the storage modulus was increased about 257~283% in the measuring temperature range of $-25^{\circ}C$ to $50^{\circ}C$. The result also exhibited that the carbonized PAN nanofibers were distributed uniformly and compactly in the unsaturated polyester, connecting the matrix three-dimensionally through the thickness direction of each specimen. It seemed that such the fiber distribution played a role in reducing the electrical resistivity as well as in improving the dynamic storage modulus.

Carbon nanofiber-reinforced polymeric nanocomposites

  • Jang, Changwoon;Hutchins, John;Yu, Jaesang
    • Carbon letters
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    • v.14 no.4
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    • pp.197-205
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    • 2013
  • Five vapor-grown carbon nanofiber (VGCNF) reinforced vinyl ester (VE) nanocomposite configurations were fabricated, imaged, and mechanically tested in order to obtain information on the influence and the interactions of the role of the microstructure at lower length scales on the observed continuum level properties/response. Three independent variables (the nanofiber weight fraction and two types of nanofiber mixing techniques) were chosen to be varied from low, middle, and high values at equally spaced intervals. Multiple mixing techniques were studied to gain insight into the effect of mixing on the VGCNF dispersion within the VE matrix. The point count method was used for both lower length-scale imaging techniques to provide quantitative approximations of the magnitude and the distribution of such lower length-scale features. Finally, an inverse relationship was shown to exist between the stiffness and strength properties of the resulting nanocomposites under uniaxial quasistatic compression loading.

Fabrication of Carbon Nanofiber/Cu Composite Powder by Electroless Plating and Microstructural Evolution during Thermal Exposure (무전해 도금에 의한 탄소나노섬유/Cu 복합 분말 제조 및 열적 안정성)

  • Kim In-soo;Lee Sang-Kwan
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.39-42
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    • 2004
  • Carbon nanofiber/Cu composite powder has been fabricated by electroless plating process. Microstructural evolution of the composite powder after heat treatment under vacuum, hydrogen and air environment was investigated. A dispersed carbon nanofiber coated by copper was produced at the as-plated condition. Carbon nanofiber is coated uniformly and densely with the plate shaped copper particles. The copper plates on the carbon nanofiber aggregate during the thermal exposure at elevated temperature in vacuum and hydrogen in order to reduce surface energy. The thermal exposure of the composite powder in air at $400^{\circ}C$ for 3 hours leads to the spherodization of the composite powder owing to oxidation of copper.

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