• 폴리머
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• 제34권3호
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• pp.198-201
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• 2010

탄소나노튜브의 응집력을 완화하기 위한 표면 개질과 고분자 소재와의 상용성을 유도하기 위하여, 친수성 고분자를 도입하는 연구를 진행하였다. 산처리를 통한 표면 기능화를 시행하였으며, 카복실기 도입 탄소나노튜브를 thionyl chloride을 사용하여 acyl chloride로 치환한 후 저분자량의 아민 말단 poly(ethylene oxide)를 공유결합으로 도입하였다. TGA를 통하여 탄소나노튜브 표면에 도입된 고분자의 함량을 계산하였으며, 탄소나노튜브 표면에 도입된 고분자의 표면 형상을 SEM과 TEM을 통하여 직경이 증가하는 것을 확인할 수 있었다.

• Journal of Electrical Engineering and Technology
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• 제3권1호
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• pp.115-120
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• 2008

Use of the carbon nanotube is superior to general powder state materials of mechanical and electrical properties. Because its ratio of diameter and length (aspect ratio) is very large, it has been known as a type of ideal nano-reinforcement material. Based on this advantage, the existing carbon black of semiconductive shield materials used in power cables can acquire excellent properties by using a small amount of carbon nanotubes. Thus, we investigated the thermal properties of the carbon nanotube, such as thermal conductivity, specific heat, and DSC (Differential Scanning Calorimetry). We found that a high thermal resistance level is demonstrated by using a small amount of carbon nanotubes. As a result, this tendency confirms high cross-linking density in a new network in which the carbon nanotube between carbon black constitute molecules shows a bond by similar constructive properties.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.153-156
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• 2005

Nondestructive sensing of electrospun PYDF web and multi-wall carbon nanotube (MWCNT)/epoxy composites were investigated using electro-micromechanical technique. Electrospinning is a technique used to produce micron to submicron diameter polymeric fibers. Electrospun PVDF web was also evaluated for the sensing properties by micromechanical test and by measurement electrical resistance. CNT composite was especially prepared for high volume contents, 50 vol% of reinforcement. Electrical contact resistivity on humidity sensing was a good indicator for monitoring as for multifunctional applications. Work of adhesion using contact angle measurement was studied to correlate acid-base surface energy between carbon fiber and CNF composites, and will study furher for interfacial adhesion force by micromechanical test.

• Advances in nano research
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• 제3권4호
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• pp.193-206
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• 2015

The present paper investigate the elastic buckling of chiral double-walled carbon nanotubes (DWCNTs) under axial compression. Using the non-local elasticity theory, Timoshenko beam model has been implemented. According to the governing equations of non-local theory, the analytical solution is derived and the solution for non-local critical buckling loads is obtained. The numerical results show the influence of non-local small-scale coefficient, the vibrational mode number, the chirality of carbon nanotube and aspect ratio of the (DWCNTs) on non-local critical buckling loads of the (DWCNTs). The results indicate the dependence of non-local critical buckling loads on the chirality of single-walled carbon nanotube with increase the non-local small-scale coefficient, the vibrational mode number and aspect ratio of length to diameter.

• Structural Engineering and Mechanics
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• 제33권2호
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• pp.193-213
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• 2009

In this paper structural analysis of nonhomogeneous nanotubes has been carried out using nonlocal elasticity theory. Governing differential equations of nonhomogeneous nanotubes are derived. Nanotubes include both single wall nanotube (SWNT) and double wall nanotube (DWNT). Nonlocal theory of elasticity has been employed to include the scale effect of the nanotubes. Nonlocal parameter, elastic modulus, density and diameter of the cross section are assumed to be functions of spatial coordinates. General Differential Quadrature (GDQ) method has been employed to solve the governing differential equations of the nanotubes. Various boundary conditions have been applied to the nanotubes. Present results considering nonlocal theory are in good agreement with the results available in the literature. Effect of variation of various geometrical and material parameters on the structural response of the nonhomogeneous nanotubes has been investigated. Present results of the nonhomogeneous nanotubes are useful in the design of the nanotubes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1410-1411
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• 2011

Tip-type carbon nanotube(CNT) based electron emitters were fabricated by forming a hafnium(Hf) interlayer between the CNT and the substrate. The CNTs were deposited by using the electrophoretic deposition method and thermally treated. No significant change in the microscopic structure of the CNTs, such as the ratio of length to diameter, was observed after the deposition of Hf interlayer and thermal treatment. As compared with the CNT emitter without the Hf-interlayer and thermal treatment, the CNT emitter with the Hf-interlayer and thermal treatment showed noticeably improved electron-emission properties due to the enhanced adhesion.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 합동춘계학술대회 논문집 전기물성,응용부문
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• pp.185-186
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• 2008

Use of the carbon nanotube is superior to general powder state materials of dispersion property. Because its ratio of diameter and length(aspect ratio) is very large, it has been known as a type of ideal nano-reinforcement composite. It used solution mixing method for specimen fabrication. To research dispersion property, we used FE-SEM(Field Emission Scanning Electron Microscope) and AFM(Atomic Force Microscope). As a result, this tendency confirms new conductivity network in which the carbon nanotube between carbon black constitute molecules shows a bond by similar constructive property.

• Advances in nano research
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• 제2권4호
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• pp.199-210
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• 2014

Carbon nanotubes have exceptional mechanical, thermal and electrical properties, and are considered for high performance structural and multifunctional composites. In the present study, the natural frequencies of aligned single walled carbon nanotube (CNT) reinforced composite beams are obtained using shear deformable composite beam theories. The Ritz method with algebraic polynomial displacement functions is used to solve the free vibration problem of composite beams. The Mori-Tanaka method is applied to find the composite beam mechanical properties. The continuity conditions are satisfied among the layers by modifying the displacement field. Results are found for different CNT diameters, length to thickness ratio of the composite beam and different boundary conditions. It is found that the use of smaller CNT diameter in the reinforcement element gives higher fundamental frequency for the composite beam.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.123-126
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• 2001

Multiwalled carbon nanotubes were massively produced by the catalytic reaction of C$_2$H$_2$ - Fe(CO)$\sub$5/ mixture at 750 - 950$^{\circ}C$ in a quartz tube reactor and over quartz substrates. Well-aligned MWNT array grows perpendicular to the quartz tube reactor and the quartz substrates at an average of 60 nm in diameter and up to several thousands of micrometers in length. This method does not require any pretreatment of substrates and CNTs are grown at atmospheric pressure. It could be suitable for mass production of multiwalled nanotubes. Scanning electron microscope and transmission electron microscope images of the nanotubes deposited on the substrates allowed us to monitor the quality of MWNTs grown under different operating conditions.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.60-63
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• 2004

Recently, carbon nanotubes(CNTs) have been demonstrated to possess remarkable mechanical and electronic properties, in particular, for field emission applications. Its high aspect ratio and extremely small diameter, hollowness, together with high mechanical strength and high chemical stability, are advantages for use in field emitter. In this paper, we demonstrate electrical discharge properties from carbon nanotube cathode electrodes to use as an emitter electrode of vacuum gauges. Vertically aligned $2{\times}2mm^2$ CNT arrays on the silicon substrate were synthesized by the thermal CVD method on Fe catalytic metal, and a glass patterning by the sand blast method and the silicon/glass anodic bonding processes were applied to make samples with 2 electrodes. The field emission was examined under the vacuum range of $10^{-3}$ Torr.