• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.25.2-25.2
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• 2010

CNT(Carbon Nanotube)는 특이한 구조 및 뛰어난 물성을 갖고 있어, 여러가지 분야에 응용 가능한 신소재로서 연구되어 왔다. 또한 모양 및 구조에 따라 기계, 전기, 화학적인 특성이 달라 다양한 분야에서 활용이 가능하다. 외국에서는 FED tip, TR, 디스플레이 소자, 수소저장체, 고강도 복합체 및 대 표면적 전극 등 CNT의 다양한 특성을 이용한 응용이 연구되고 있는 반면, 국내에서는 이론연구와 합성연구에 편중되어 있다. 본 연구에서는 열 화학 기상법 (Thermal CVD)을 이용하여 MWNT(Multi-wall nano tube)를 성장시켜 촉매두께, 온도, gas변수에 따른 CNT의 양상을 분석하였다. Ni catalyst는 DC magnetron sputter를 이용하여 5~50nm 두께로 증착하였으며, 성장온도는 $800^{\circ}C$에서 $950^{\circ}C$까지 변화시켰다. 기판의 pre-treatment 로 ammonia($NH_3$) gas를 주입한 후, carbon precursor인 methane($CH_4$) gas와 $H_2$ dilute gas를 1:4의 비율로 주입하여 CNT를 성장시켰다. FE-SEM과 TEM, 그리고 XRD를 이용해 성장된 CNT의 형상 및 구조를 분석한 결과, 낮은 온도에서는 100nm이상의 두께를 갖는 수직형상의 MWNT가 성장되었으며, $900^{\circ}C$이상의 높은 온도에서는 20nm이하의 amorphous carbon nano rod가 성장되었다. 각각의 MWNT, carbon nano rod는 온도가 높을수록 직경이 증가하는 추세를 나타냈으며, Ni catalyst가 얇아질수록 수직형상을 갖는 결과가 나타났다. 또한 ammonia gas의 pre-treatment여부에 따라 CNT의 수직 형상이 좌우되는 결과를 확인하였다. 향후 성장된 MWNT의 최적 조건을 도출하여 디스플레이 소자인 FED(Field Emission Display)분야 등에 응용 가능할 것으로 전망된다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.739-744
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• 2007

In this paper, we have investigated mechanical and chemical properties by changing the content of carbon nanotube, which is component part of semiconductive shield in underground power transmission cable. Specimens were made of sheet with the eight of those for measurement. The condition of specimens was a solid sheet. Chemical properties of specimens was measured by FT-ATR (Fourier Transform Attenuated Total Reflectance). Stress-strain of specimens was measured by TENSOMETER 2000. A speed of measurement was 200[mm/min], ranges of stress and strain were 400[Kgf/Cm] and 600[%]. We could observe (unctional group (C=O, carbonyl group) of specimens through FT-ATR. From these experimental result, the concentration of functional group [C=O] was high accor야ng to increasing the content of carbon nanotube. We could know CNT/EEA was excellent more than other specimens from above experimental results. In Addition, the elongation ratio was decreased, and yield strength was increased according to increasing the content of carbon nanotube. Also, from these experimental result, we could know that a small amount of CNT/EEA has a excellent mechanical and chemical properties.

• Advances in nano research
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• v.17 no.1
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• pp.19-32
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• 2024

Functionally graded-carbon nanotube (FG-CNT) is expected to be a new generation of materials with a wide range of potential applications in technological fields such as aerospace, defense, energy, and structural industries. In this paper, an exact finite strip method for functionally graded-carbon nanotube sandwich plates is developed using first-order shear deformation theory to get the exact natural frequencies of the plates. The face sheets of the plates are made of FG-CNT with continuous and smooth grading based on the power law index. The equations of motion have been generated based on the Hamilton principle. By extracting the exact stiffness matrix for any strip of the sandwich plate as a non-algebraic function of natural frequencies, it is possible to calculate the exact free vibration frequencies. The accuracy and efficiency of the current method is established by comparing its findings to the results of the literature works. Examples are presented to prove the efficiency of the generated method to deal with various problems, such as the influence of the length-to-height ratio, the power law index, and a core-to-face sheet thickness of the single and multi-span sandwich plates with various boundary conditions on the natural frequencies. The exact results obtained from this analysis can check the validity and accuracy of other numerical methods.

• Membrane and Water Treatment
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• v.13 no.6
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• pp.259-290
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• 2022

Carbon nanotubes (CNTs), due to their excellent physical, chemical and mechanical properties and their ability to prepare new membranes with attractive properties, have found applications in water and wastewater technology. CNT functionalization, which involves the introduction of different types of functional groups into pure CNTs, improves the capabilities of CNT membranes for water and wastewater treatment. It turns out that CNT-based membranes have many advantages, including enhanced water permeability, high selectivity and anti-fouling properties. However, their full-scale application is still limited by their high cost. With their tremendous separation efficiency, low biofouling potential and ultra-high water flux, CNT membranes have the potential to be a leading technology in water treatment in the future, especially in desalination.

• Journal of Electrical Engineering and Technology
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• v.3 no.1
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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.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.574-581
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• 2016

In this study, CNT functionalized with pyrrolidine ring via 1,3-dipolar cycloaddition reaction with various amino acid and aldehyde was synthesized. Metallocene was subsequently immobilized on the functionalized CNT and CNT/polyethylene composite was prepared via in-situ ethylene polymerization. The polymerization activities of metallocene supported on CNT functionalized with glycine and benzaldehyde (Gly+BA-CNT) were similar to those of metallocene supported on CNT functionalized with N-benzyloxycarbonylglycine and paraformaldehyde (Z-Gly+PFA-CNT) although its Zr content was lower than that of Z-Gly+PFA-CNT. In the case of metallocene supported on Z-Gly+PFA-CNT, the even distribution of active sites hindered the diffusion of ethylene monomer and cocatalyst MAO due to steric hindrance during ethylene polymerization. Compared to polyethylene produced from homogeneous metallocene catalysts, CNT/PE composites had a higher initial degradation temperature ($T_{onset}$) and maximum mass loss temperature ($T_{max}$). It suggests that pyrrolidine functionalized CNT is uniformly dispersed and strongly interacted with the PE matrix, enhancing the thermal stability of PE.

• Journal of Wetlands Research
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• v.19 no.2
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• pp.246-251
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• 2017

This study was carried out to evaluate the possibility of Chromium removal by 3 different kinds of adsorbents, where activated carbon(AC), carbon nanotube(CNT) and layered double hydroxides(LDHs) were employed. The highest surface area was shown in AC and pore volume was in CNT which were $1028.1m^2{\cdot}g^{-1}$ and $0.829cm^2{\cdot}g^{-1}$, respectively. AC and CNT are composed of more than 99% carbon. AC has shown the possibility of chromium removal more than 80.2% under the acidic pH condition.

• Journal of Sensor Science and Technology
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• v.31 no.3
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• pp.163-167
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• 2022

In this study, we investigated a carbon nanotube (CNT) film sensor to detect hazardous and noxious substances distributed in seawater. The response change of the sensor was studied according to environmental temperature, and its temperature coefficient of resistance (TCR, α) was measured. The temperature of the CNT film (~50 ㎛) was in the range of 20-50 ℃, and αCNT was calculated to be -0.0011 %/ ℃. We experimentally confirmed that the CNT film had a smaller TCR value than that of the conventional sensor. Therefore, we investigated the response change of the CNT sensor according to temperature. The CNT sensor showed a relatively small error of approximately 2.3 % up to 30 ℃, which is within the temperature range of the seawater of the Korean Peninsula. However, when the temperature exceeded 40 ℃, the error in the CNT sensor increased by more than 5.2 %. We fabricated a metal oxide (ITO, indium-tin-oxide) film and compared its performance with that of the CNT sensor. The ITO sensor showed an error of >12.5 % at 30 ℃, indicating that in terms of the stability of the sensor to temperature, the CNT film sensor has superior performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.164-165
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• 2006

Carbon nanotube(CNT)-reinforced poly(ethylene-co-ethyl acrylate)(EEA) nanocomposites were prepared by melt mixing with a Haake internal mixer. The CNT loading was vaned from 0 to 20 wt%. The changes m CNT dispersion and shape were investigated with FE-SEM observation with and without the Tensile strain of 40%. The CNT was protruded over the fracture surface upon Tensile strain, which is a very interesting behavior.

• Journal of the Semiconductor & Display Technology
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• v.10 no.4
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• pp.37-42
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• 2011

In this paper, novel carbon nanotube (CNT)-filled Solderable electrically conductive adhesive (ECA) and joining process have been developed. To investigate the bonding characteristics of CNT-filled Solderable ECA, three types of Solderable ECAs with different CNT weight percent (0, 0.1, 1wt%) were formulated. For a joining process, the quad flat package (QFP) chip was used. The QFP chip had a size of $14{\times}14{\times}2.7$ mm and a 1 mm lead pitch. The test board had a Cu daisy-chained pattern with 18 ${\mu}m$ thick. After the bonding process, the bonding characteristics such as morphology of conduction path, electrical resistance and pull strength were measured for each formulated ECAs. As a result, the electrical and mechanical bonding characteristics for a QFP joints using CNT-filled ECA were improved about 10% compared to those of QFP joints using ECA without CNT.