Papers by Keyword: Multi-Walled Carbon Nanotube (MWCNT)

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Authors: Ai Hong Liu
Abstract: Carbon nanotubes (CNTs) may play a significant role in the biomedical field in future. Therefore, it is imperative to thoroughly investigate the toxicity and the biocompatibility of CNTs. However, the data about the toxicity of carbon nanotubes in vivo is poor or contradictory. In this study, rats were instilled with different dose mutil-wall carbon nanotubes (MWCNTs) by intravenous injection and euthanized 90d after the single treatment for histopathological study of the lungs and other organs. All rats survived within our experimental period and no large changes in their weights appeared. It is confirmed that all MWCNTs-exposed rats suffered multiple lesions. Obvious changes of the structure of lung tissue and the micrograph of MWCNTs in lung tissue were observed by TEM, while other tissues were in order. The results suggest that MWCNTs can induce lung toxicity in the expose modes of intravenous injection.
Authors: Xiao Wei Zhou, Guang Ming Wu, Guo Hua Gao, Hui Yu Yang, Ji Chao Wang
Abstract: In this paper, V2O5-Multiwall Carbon Nanotubes (MWCNTs) composite film is prepared through sol-gel technique and dip-coating method. MWCNTs pretreated by mixed acid, H2O2 and cheap V2O5 powder are used as raw materials. The morphology, structure and components of the composite film are characterized by corresponding testing instruments. The final electrochemical measurements indicate that: the V2O5-MWCNTs composite film as cathode materials for lithium batteries exhibits better electrochemical performance than ordinary V2O5 film.
Authors: Qi Zhi Diao, Yuan Li, Mi Zhou, Guo Ming Xie
Abstract: A new electrochemical immunosensor for serum myeloperoxidase (MPO) has been developed based on the self-assembly multilays of multi-walled carbon nanotubes (MWNTs), thionine (THI), gold nanoparticles (GNPs) and chitosanon (CHIT) on the glassy carbon electrode (GCE). The antibody of MPO (anti-MPO) was absorbed on the surface of GNPs monolayer. Horseradish peroxidase (HRP) was employed to block non-specific binding and amplify the response current signal. It was observed that the peak current was linear with the MPO concentration in a range of 2.5-125 µgl-1. The detection limit was 1.425 µgl-1 (S/N=3). Correlation analysis showed that this new immunosensor assay has a significant correlation with enzyme-linked immunosorbent assay (ELISA) (r=0.96, p>0.05) for 40 clinical specimens.
Authors: Tung Feng Hsieh, Chia Chih Chuang, Ming Yang Liu, Yu Chuan Chou, Chi Min Shu
Abstract: A nanocomposite electrode of vertically aligned multi-walled carbon nanotubes (MWCNTs) on gold was fabricated to improve the specific capacitance and power density of the conventional supercapacitor. The novel supercapacitor built from MWCNTs and gold electrode showed a very high specific capacitance of 92.74 F/g using cyclic voltammetry (CV) at 10 mV/s, and 96.43 F/g was measured at 100 Hz. This nanocomposite electrode greatly enhanced the utilization efficiency of supercapacitor electrode material, low material cost and provided both high capacitance and power density. It was shown that the nanocomposite electrode based on vertically aligned carbon nanotube electrode had the characteristics of high specific capacitance.
Authors: Wei Tai Huang, Hsun Heng Tsai, Der Ho Wu, Wei Tai Lee
Abstract: This paper proposes a new lubricant environment when MWCNTs was used in MQL for AISI 304L in the turning machine. The effects of dry cutting, MQL cutting, and MWCNTs/MQL were compared to the surface roughness of work pieces, cutting temperature and the tool wear. In the past, the studies have shown that the MQL process can prolong tool life and improve surface accuracy in machining. The purpose of using MWCNTs suspensions is to increase the thermal conductivity of cutting fluid and to reduce the temperature during the cutting and decrease the thermal wear of tool simultaneously. The present study investigated the characterization of the MWCNTs was applied into MQL during the turning process of AISI 304L experimentally. The results showed that the MWCNTs will be a very good additive to MQL, not only with the benefits of improving surface roughness but also with ability of prolonging life of tool by reducing the cutting temperature in turning AISI 304L.
Authors: Yong Woo Kim, Eun Nara Cho, Soo Chang Choi, Deug Woo Lee
Abstract: M-CNTs (Multiwall Carbon Nano Tubes) can be used as an electrode, transferring electrons and heat very easily. This property helps transfer electrons created in TiO2 layer of DSSC (Dye-sensitized Solar Cell). CNTs layer with TiO2 utilized for the photocatalyst is expected to contribute to improve the efficiency of the solar cell. The Photocatalyst of TiO2 thin film was manufactured from titanium isopropoxide, ethanol, and HCl by a sol-gel process. To determine the property of TiO2 thin film with CNT, we performed to mix acid dispersed CNT in TiO2 Sol-gel and make coating membranes using sol-gel with different densities of CNT. It was found that the crystal structure changed from the anatase phase to the rutile phase having higher efficiency by XRD measure after treatment of high temperature sintering. To demonstrate the property of each sample, the transmittance of the TiO2 thin film was measured by a spectrometer and dispersion of CNT of the thin film was measured by SEM. In conclusion, the capacitance as the parameter which can affect performance of DSSC was investigated.
Authors: N. Duangphattra, C. Aramphongphun
Abstract: This research work studies the effects of processing conditions on mechanical properties of polymer nanocomposites. Polypropylene (PP) nanocomposites reinforced with 0.5 and 2.5 %wt multiwall carbon nanotubes (MWCNTs) were prepared via melt compounding and formed by injection molding. 2k Full Factorial design was used to plan the experiments and determine the influences of the processing conditions on mechanical properties and carbon nanotube dispersion in the nanocomposites. These conditions consist of five factors: (a) %wt content of MWCNTs (0.5 and 2.5 %wt), (b) barrel temperature (190 and 220°C), (c) injection velocity (25 and 45 mm/sec), (d) screw rotational speed (75 and 227 rpm) and (e) holding pressure (45 and 65 bar) while injection pressure and cooling time were set at 75 bar and 50 sec, respectively, for all conditions. The samples were examined by Young’s modulus and tensile strength using a Universal Testing Machine (UTM). In addition, Scanning Electron Microscopy (SEM) was applied to study the dispersion of carbon nanotubes in the nanocomposites. The results showed that PP/MWCNT nanocomposites had Young’s modulus of 1,740 MPa and tensile strength of 34.5 MPa while original PP had 1,450 MPa and 28 MPa, respectively. Therefore, the mechanical properties were improved significantly with the content of MWCNTs. Full Factorial experiments investigate that significant factors are %wt, barrel temperature, injection velocity, and screw rotational speed. Moreover, SEM showed that a high content of MWCNTs led to a highly oriented skin layer with well-dispersed MWCNTs.
Authors: Zhi Feng Zeng, Hai Yan Zhang, Xi Duo Hu
Abstract: The LiFePO4/MWCNTs composite used as cathode was synthesized by ball milling. XRD and SEM experiments demonstrated that MWCNTs didn’t change the olivine structure of LiFePO4 and that MWCNTs decentralized into the grains of LiFePO4 and working as electric bridge improving the electrochemical properties of LiFePO4. The electrochemical performance of the composite electrodes with different MWNTs in diameter were studied by button cell. The result indicated that the composite with largest diameter MWNTs exhibited best electrochemical performance. The first charge-discharge specific capacity of the composite with MWNTs of 60-100nm in diameter were 136mAh/g-1 and 129 mAh/g-1 respectively at 0.1C rate under room temperature. The difference between charge-discharge platforms of the composite electrode was the least compared to the others. This phenomenon showed that the material had the largest chemical diffusion coefficient of lithium. At the same time, the capacity of the composite only lost 4.0% after 10 cycles and kept constant after 20 cycles.
Authors: Zhi Ping Zhu, Ke Long Huang, Yi Zhou
Abstract: The multi-walled carbon nanotubes (MCNTs) are used as an adsorbent to remove humic acid (HA) from boiler feedwater. The experiment carries on in different temperatures, different MCNTs dosages, different pH value and different HA initial concentration to study adsorption HA property by MCNTs. The adsorption kinetics is well fitted with pseudo-second-order rate model, the adsorption mechanism is mainly attributed to the π-π electron-donor-acceptor interaction between the aromatic ring of HA and the surface carboxylic groups of MCNTs. The adsorption isotherms are fitted better with Langmuir than Freundlich models, the parameters of equilibrium constant, standard free energy (ΔG), standard enthalpy (ΔH), and standard entropy changes (ΔS) are calculated according to experiments, which shows adsorption of HA onto PAC is an exothermic process.
Authors: Kishore T. Kashyap, K. Bagaria Puneeth, Aniruddha Ram, Praveenath.G. Koppad
Abstract: Multiwalled carbon nanotubes (MWCNTs) were added to Aluminium alloy AA6063 by powder metallurgy route. The samples were compacted, sintered and microhardness was measured on sintered samples. The weight fraction of MWCNTs was varied between 0.5-2.5%. The hardness of the composite has been observed to increase. The ageing curves after solutionizing and artificial ageing have been plotted for various weight fractions of MWCNTs in AA6063 alloy. Electroless copper coating was given to CNTs and the hardness of the samples with Cu coated CNTs in AA6063 showed a higher hardness than the samples without Cu coating on CNTs. Further the ageing curves showed a faster kinetics with increase of MWCNTs in Al6063. This result applied to coated CNTs in 6063 which also showed accelerated ageing kinetics during artificial ageing gives inherent evidence for the Arsenault’s thermal mismatch model of strengthening of MWCNT/Al nanocomposite.
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