• International Journal of Precision Engineering and Manufacturing
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• v.9 no.3
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• pp.18-21
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• 2008

The study deals with the effects of parameters in the synthesis of carbon nanotubes in liquid nitrogen to find the most appropriate conditions such as electrical voltage and time that give carbon nanotubes with large volume and less proportion of impurity, which is a non-nanotubed carbon. The experiment employed the method of arc-discharge between graphite cathode and anode which are immersed in liquid nitrogen. The electrical DC current of 60A and 70A were applied with the time period ranging from 10 seconds to 25 seconds. It was found that the electrical current of 60A and 13 seconds arc-discharge time allowed the largest volume of carbon nanotubes generation. The longer time leads to more impurities around the carbon nanotubes. By the filtration of CNTs-suspended solution using 0.2 micrometers porous paper filter and the characterization using TEM, the carbon nanotubes synthesized in the study were approximately 25 layers multi-walled nanotubes with the average diameter of 18.2 nanometers.

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.2
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• pp.122-130
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• 2003

Li/S 이차전지의 유황양극의 전기전도도를 향상시키고 유황이 충방전시 전해질내로 용출되는 것을 방지하기 위하여 multi-walled carbon nanotubes (MWNTs)를 thermal CVD 방법으로 제조하여 유황양극에 첨가하였다. 실험결과 첫 사이클에서 Li/S 이차전지의 방전용량은 485mAh/g-sulfur이었고, MWNT 첨가 이후에 유황양극의 cycle life와 rate-capability가 향상되는 것을 관찰할 수 있었다. 그러므로 MWNT는 polysulfide를 유황양극에 흡착시키는 동시에 good electric conductor로서 작용한다는 것을 알 수 있었다.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.220-220
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• 2006

Rheological and electrical properties of the polycarbonate (PC) / multi-walled carbon nanotube (MWNT) were studied. The MWNT was funtoinalized by treating with the hydrogen peroxide ($H_{2}O_{2}$). The electrical conductivity showed higher value for the PC/MWNT ($H_{2}O_{2}$ treated, freeze drying) composites compared that of the PC/MWNT ($H_{2}O_{2}$ treated, thermal drying) composites. From the results of the morphological, rheological, and electrical properties of the PC/MWNT composites, it is suggested that the electrical and rheological properties of the PC/MWNT composites are affected by the MWNT-MWNT network structure which is related with the MWNT morphologies such as the degree of aggregation and aspect ratio of the MWNT.

• Polymer(Korea)
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• v.34 no.3
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• pp.198-201
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• 2010

We have worked a surface modification to release a strong agglomeration of multi-walled carbon nanotube(MWCNT) and a incorporation of hydrophilic polymer to improve compatibility between MWCNT and polymers. Carboxylated MWCNT was easily obtained by acid treatment and the carboxylate was converted to acylchloride by thionyl chloride. Then, we tried one more synthesizing routes to achieve covalent bonds with poly(ethylene oxide) having amine end groups of low molecular weight. We measured the polymer content on the surface of MWCNT by TGA and observed increased diameter of MWCNT by SEM and TEM analysis.

• Carbon letters
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• v.15 no.2
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• pp.117-124
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• 2014

Conductive polymer composites (CPCs) consist of a polymeric matrix and a conductive filler, for example, carbon black, carbon fibers, graphite or carbon nanotubes (CNTs). The critical amount of the electrically conductive filler necessary to build up a continuous conductive network, and accordingly, to make the material conductive; is referred to as the percolation threshold. From technical and economical viewpoints, it is desirable to decrease the conductive-filler percolation-threshold as much as possible. In this study, we investigated the effect of polymer/conductive-filler interactions, as well as the processing and morphological development of low-percolation-threshold (${\Phi}c$) conductive-polymer composites. The aim of the study was to produce conductive composites containing less multi-walled CNTs (MWCNTs) than required for pure polypropylene (PP) through two approaches: one using various mixing methods and the other using immiscible polymer blends. Variants of the conductive PP composite filled with MWCNT was prepared by dry mixing, melt mixing, mechanofusion, and compression molding. The percolation threshold (${\Phi}c$) of the MWCNT-PP composites was most successfully lowered using the mechanofusion process than with any other mixing method (2-5 wt%). The mechanofusion process was found to enhance formation of a percolation network structure, and to ensure a more uniform state of dispersion in the CPCs. The immiscible-polymer blends were prepared by melt mixing (internal mixer) poly(vinylidene fluoride) (PVDF, PP/PVDF, volume ratio 1:1) filled with MWCNT.

• Advances in concrete construction
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• v.15 no.2
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• pp.75-84
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• 2023

Currently, polymer matrix nanocomposites (PMCs) are a prominent area of research due to their outstanding mechanical, thermal, and durability properties. The increase in recent studies justifies the possibility of using PMCs in structural retrofitting and reconstruction of damaged infrastructure and serving as new structural material. Using nanotechnology, nanocomposite panels in flooring combine concrete and steel, providing a very high level of performance. In sports flooring, high-performance concrete has become a challenge for reducing sports injuries and refinement in rehabilitation. As a composite material, this type of resistant concrete is one of the most durable and complex multi-phase materials. This article uses polyvinyl alcohol polymer (PVC) and multi-walled carbon nanotubes as concrete matrix fillers. Solution methods have been used for dispersing PVC and carbon nanotubes in concrete. The water-cement ratio, carbon nanotube weight ratio, and heat treatment parameters influenced the concrete nanocomposite's tensile and compressive strength. The dispersion of carbon nanotubes in cement paste and the observation of nano-microcracks in concrete was evaluated by scanning electron microscope (SEM).

• Proceedings of the Korean Vacuum Society Conference
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• 2009.08a
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• pp.109-109
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• 2009

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.50-51
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.48-49
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.38-39
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• 2004