• Title, Summary, Keyword: Multi-Walled Carbon Nanotube (MWCNT)

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Cycling Performance of Supercapacitors Assembled with Polypyrrole/Multi-Walled Carbon Nanotube/Conductive Carbon Composite Electrodes

  • Paul, Santhosh;Kim, Jae-Hong;Kim, Dong-Won
    • Journal of Electrochemical Science and Technology
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    • v.2 no.2
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    • pp.91-96
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    • 2011
  • Polypyrrole (PPy)/multi-walled carbon nanotube (MWCNT)/conductive carbon (CC) composites are synthesized by the chemical oxidative polymerization method. The morphology analysis of the composite materials indicates uniform coating of PPy over MWCNTs and conductive carbon. The electrochemical performances of PPy/MWCNT/CC composites with different compositions are evaluated in order to optimize the composition of the composite electrode. Galvanostatic chargedischarge measurements and electrochemical impedance spectroscopy studies prove the excellent cycling stability of the PPy/MWCNT/CC composite electrodes.

Preparation and rheological behavior of polystyrene/multi-walled carbon nanotube composites by latex technology

  • Woo, Dong-Kyun;Kim, Byung-Chul;Lee, Seong-Jae
    • Korea-Australia Rheology Journal
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    • v.21 no.3
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    • pp.185-191
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    • 2009
  • Polystyrene/multi-walled carbon nanotube (PS/MWCNT) composites were prepared by the use of latex technology. The monodisperse PS latex was synthesized by an emulsifier-free emulsion polymerization from styrene/potassium persulfate/water system in the presence of ethanol. The MWCNTs were first treated with acid mixture to eliminate impurities, dispersed in deionized water driven by ultrasonicator, and then mixed with the PS latex. From these mixtures, PS/MWCNT composites were prepared by freeze-drying and subsequent compression molding. In the small-amplitude oscillatory shear experiments, both complex viscosity and storage modulus increased with increasing MWCNT content. A pronounced effect of MWCNT content was observed, resulting in larger storage modulus and stronger yield behavior at low frequencies when compared to unmodified PS. It showed a transition from viscous to elastic behavior with increasing MWCNT content. Over the MWCNT content of 3 wt%, the storage modulus was higher than the loss modulus across all frequencies.

Preparation and Properties of Aniline Terminated Waterborne Polyurethane/Multi-walled Carbon Nanotube Composite Coating Solutions (Aniline Terminated Waterborne Polyurethane/Multi-walled Carbon Nanotube 복합 코팅 용액의 제조 및 물성)

  • Hong, Min Gi;Kim, Byung Suk;Song, Ki Chang
    • Korean Chemical Engineering Research
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    • v.50 no.3
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    • pp.403-409
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    • 2012
  • Polyurethane prepolymers were prepared from poly (carbonate diol), isophrone diisocyanate, and dimethylol propionic acid. Then, aniline terminated waterborne polyurethane dispersion (ATWPUD) was synthesized by capping aniline on the NCO group of the prepolymer. Subsequently, ATWPUD was mixed with multi-walled carbon nanotube (MWCNT) to yield coating solutions, and the mixture was coated on the polycarbonate substrate. The surface resistance ($10^{7.6}{\sim}10^{7.7}{\Omega}/cm^2$) of coating films from ATWPUD showed better conducting properties than that ($10^{10.9}{\Omega}/cm^2$) from pure waterborne polyurethane dispersion (WPUD) when MWCNT was mixed. Also, the surface resistance of coating films was increased, but the pencil hardness and adhesion were decreased with increasing the amount of MWCNT added in the ATWPUD.

Characterization and influence of shear flow on the surface resistivity and mixing condition on the dispersion quality of multi-walled carbon nanotube/polycarbonate nanocomposites

  • Lee, Young Sil;Yoon, Kwan Han
    • Carbon letters
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    • v.16 no.2
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    • pp.86-92
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    • 2015
  • Multi-walled carbon nanotube (MWCNT)/polycarbonate (PC) nanocomposite was prepared by direct melt mixing to investigate the effect of the shear rate on the surface resistivity of the nanocomposites. In this study, an experiment was carried out to observe the shear induced orientation of the MWCNT in the polymer matrix using a very simple melt flow indexer with various loads. The compression-molded, should be eliminated. MWCNT/PC nanocomposite sample exhibited lower percolation thresholds (at 0.8 vol%) and higher electrical conductivity values than those of samples extruded by capillary and injection molding. Shear induced orientation of MWCNT was observed via scanning electron microscopy, in the direction of flow in a PC matrix during the extrusion process. The surface resistivity rose with increasing shear rate, because of the breakdown of the network junctions between MWCNTs. For real applications such as injection molding and the extrusion process, the amount of the MWCNT in the composite should be carefully selected to adjust the electrical conductivity.

스프레이 법으로 제작된 MWCNT 투명전도막의 특성

  • Jang, Gyeong-Uk
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.244-244
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    • 2009
  • Carbon nanotubes (CNTs) have excellent electrical, chemical stability, mechanical and thermal properties. In this paper, networks of Multi-walled carbon nanotube (MWCNT) materials were investigated as transparent electrode. Sensor films were fabricated by air spray method using the multi-walled CNTs solution on glass substrates. The film that was sprayed with the MWCNT dispersion for 60 sec, was 300nm thick. And the electric resistivity and the light transmittance rate are $2{\times}10^2{\Omega}cm$ and 60%, respectively.

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Effect of Nanotube Length on Rheological Characteristics of Polystyrene/Multi-walled Carbon Nanotube Nanocomposites Prepared by Latex Technology (라텍스 기법으로 제조한 폴리스티렌/다중벽 탄소나노튜브 나노복합재료의 나노튜브 길이가 유변학적 특성에 미치는 영향)

  • Woo, Dong-Kyun;Noh, Won-Jin;Lee, Seong-Jae
    • Polymer(Korea)
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    • v.34 no.6
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    • pp.534-539
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    • 2010
  • Polystyrene (PS)/multi-walled carbon nanotube (MWCNT) nanocomposites were prepared via latex technology and the effect of nanotube length on rheological properties were investigated. Monodisperse PS particle was synthesized by the emulsifier-free emulsion polymerization and two types of MWCNTs were used after surface modification to improve dispersion state and to remove impurities. Final nanocomposites were prepared by the freeze-drying process after dispersing the PS particles and the surface-modified MWCNTs in a ultrasonic bath. The effects of MWCNT content and nanotube length on rheological properties were evaluated by imposing the small-amplitude oscillatory shear flow. The PS/MWCNT nanocomposites showed that rheological properties were enhanced as the amount and length of MWCNT increased. It is speculated that the rheological characteristics of nanocomposites change from liquid-like to solid-like as the MWCNT amount increases, and the critical concentration to achieve network structure decreases as the nanotube length increases.

Preparation and characteristics of PP/CF/MWCNT nanocomposites (PP/CF/ MWCNT 나노복합체의 제조 및 특성평가)

  • Kim, Seung-Beom;Nam, Byeong-Uk;Lee, Kyu-Mann
    • Journal of the Semiconductor & Display Technology
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    • v.10 no.1
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    • pp.107-111
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    • 2011
  • Polypropylene(PP)/carbon fiber(CF)/multi-walled carbon nanotube(MWCNT) nanocomposites along with various CF and MWCNT contents were prepared in a Twin screw extruder. Electrical, mechanical property and morphology were investigated with a variation of CF and MWCNT contents. From the surface resistance of PP/CF/MWCNT composites, MWCNT can increase the conductivity of composites compared with PP/CF composites without MWCNT. It is suggested that MWCNT and CF can make the conductive network in the polymer matrix. Flexural modulus and Izod impact strength of the PP/CF/MWCNT composites were improved with the increase of CF contents. Morphology showed that length of CF in polymer matrix was shortened by torque during melt mixing with MWCNT. As a result of this phenomenon, the impact strength of composites was somewhat decreased.

Properties of impact modifier reinforced PPS/MWCNT Nanocomposite (충격보강제가 보강된 PPS (polyphenylene sulfide)/MWCNT (multi-walled carbon nanotube) 나노복합체의 물성연구)

  • Park, Ji Soo;Kim, Seung Beom;Nam, Byeong Uk
    • Journal of the Semiconductor & Display Technology
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    • v.11 no.2
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    • pp.75-80
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    • 2012
  • Polymer composites which have electrical properties have been studied in various industries. The Multi-walled carbon nanotube (MWCNT) are thought to be reinforcements for polymers because of their high aspect ratio and specially mechanical, thermal and electrical properties. We introduced MWCNT and impact modifier in order to improve thermal and mechanical properties of Polyphenylene sulfide (PPS) and give electric characteristic to PPS. The thermal properties were investigated by Differential scanning calorimeter (DSC) and Thermogravimetric analysis (TGA). The morphology, mechanical properties and electrical characteristic were performed by Field emission scanning electron microscopy (FE-SEM), Izod impact tester and surface resistance meter. As a result, we could find that the PPS/MWCNT composites have high conductivity and good mechanical properties than neat PPS resin.

Synthesis and Electrochemical Characterization of Polypyrrole/Multi-walled Carbon Nanotube Composite Electrodes for Supercapacitor Applications

  • Paul, Santhosh;Lee, Yoon-Sung;Choi, Ji-Ae;Kang, Yun-Chan;Kim, Dong-Won
    • Bulletin of the Korean Chemical Society
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    • v.31 no.5
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    • pp.1228-1232
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    • 2010
  • The nanocomposites of polypyrrole (PPy) and multi-walled carbon nanotube (MWCNT) with different composition are synthesized by the chemical oxidative polymerization method. In these composites, the MWCNTs are uniformly coated by PPy with different thickness. The electrochemical properties of the composite electrodes are investigated by cyclic voltammetry, galvanostatic charge-discharge cycling and electrochemical impedance spectroscopy. The full cells assembled with the PPy/MWCNT composite electrodes deliver initial specific capacitances ranging from 146.3 to 167.2 F/g at 0.5 mA/$cm^2$ and exhibit stable cycling characteristics. The effect of content of MWCNT in the composite on cycling performance of the cells is also investigated.

Strain-Sensing Characteristics of Multi-Walled Carbon Nanotube Sheet

  • Jung, Daewoong;Lee, Gil S.
    • Journal of Sensor Science and Technology
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    • v.22 no.5
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    • pp.315-320
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    • 2013
  • In this paper, the properties of strain sensors made of spin-capable multi-walled carbon nanotubes (MWCNTs) were characterized and their sensing mechanisms analyzed. The key contribution of this paper is a new fabrication technique that introduces a simpler transfer method compared to spin-coating or dispersion CNT. Resistance of the MWCNT sheet strain sensor increased linearly with higher strain. To investigate the effect of CNT concentration on sensitivity, two strain sensors with different layer numbers of MWCNT sheets (one and three layers) were fabricated. According to the results, the sensor with a three-layer sheet showed higher sensitivity than that with one layer. In addition, experiments were conducted to examine the effects of environmental factors, temperature, and gas on sensor sensitivity. An increase in temperature resulted in a reduction in sensor sensitivity. It was also observed that ambient gas influenced the properties of the MWCNT sheet due to charge transfer. Experimental results showed that there was a linear change in resistance in response to strain, and the resistance of the sensor fully recovered to its unstressed state and exhibited stable electromechanical properties.