scholarly journals The Effects of Multi-Walled Carbon Nanotubes and Steel Fibers on the AC Impedance and Electromagnetic Shielding Effectiveness of High-Performance, Fiber-Reinforced Cementitious Composites

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3591 ◽  
Author(s):  
Lee ◽  
Kim ◽  
Park
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
High Performance ◽  
Steel Fiber ◽  
Steel Fibers ◽  
Shielding Effectiveness ◽  
High Performance Fiber ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Electromagnetic Shielding Effectiveness

This study aimed to investigate the effect of multi-walled carbon nanotubes (MWCNTs) and steel fibers on the AC impedance and electromagnetic shielding effectiveness (SE) of a high-performance, fiber-reinforced cementitious composite (HPFRCC). The electrical conductivity of the 100 MPa HPFRCC with 0.30% MWCNT was 0.093 S/cm and that of the 180 MPa HPFRCC with 0.4% MWCNT and 2.0% steel fiber was 0.10 S/cm. At 2.0% steel fiber and 0.3% MWCNT contents, the electromagnetic SE values of the HPFRCC were 45.8 dB (horizontal) and 42.1 dB (vertical), which are slightly higher than that (37.9 dB (horizontal)) of 2.0% steel fiber content and that (39.2 dB (horizontal)) of 0.3% MWCNT content. The incorporation of steel fibers did not result in any electrical percolation path in the HPFRCC at the micro level; therefore, a high electrical conductivity could not be achieved. At the macro level, the proper dispersion of the steel fibers into the HPFRCC helped reflect and absorb the electromagnetic waves, increasing the electromagnetic SE. The incorporation of steel fibers helped improve the electromagnetic SE regardless of the formation of percolation paths, whereas the incorporation of MWCNTs helped improve the electromagnetic SE only when percolation paths were formed in the cement matrix.

scholarly journals Relationship between Three-Dimensional Steel Fiber Statistics and Electromagnetic Shielding Effectiveness of High-Performance, Fiber-Reinforced Cementitious Composites

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5125
Author(s):  
Namkon Lee ◽  
Gijoon Park ◽  
Junil Pae ◽  
Juhyuk Moon ◽  
Sungwook Kim
Keyword(s):  
Electrical Conductivity ◽  
High Performance ◽  
Steel Fiber ◽  
Fiber Content ◽  
Steel Fibers ◽  
Electrical Network ◽  
Shielding Effectiveness ◽  
Contact Points ◽  
High Performance Fiber ◽  
Electromagnetic Shielding Effectiveness

This study aims to investigate the relationship between the steel fibers and the electromagnetic wave shielding effectiveness of a high-performance fiber-reinforced cementitious composite (HPFRCC). The distribution characteristics of the steel fibers and the variation of the electrical conductivity of HPFRCC as a function of the fiber content were quantified based on micro computed tomography (CT) and impedance measurements to determine their correlations with the electromagnetic shielding effectiveness. The impedance results showed that no electrical network was formed in the composite by the steel fibers and it is difficult to manufacture HPFRCC with high-electrical conductivity using steel fibers alone without CNTs or other carbon-based materials. For the steel fiber content of greater than 0.5%, the number of contact points between the steel fibers increased significantly, and the relationship between the fiber content and the number of contact points was observed. Despite the improvement of the electrical conductivity owing to the presence of the steel fibers and to the increase in the contact points between the steel fibers, the shielding effectiveness did not increase further for the steel fiber contents equal or above 1.5%. Consequently, it was found that the factor that controls the shielding effectiveness of HPFRCC is not the electrical network of the steel fibers, but the degree of the dispersion of the individual steel fibers.

Fabrication and Properties of Multi-Walled Carbon Nanotubes Buckypaper

2015 ◽  
Vol 1108 ◽  
pp. 33-38 ◽  
Author(s):  
W.A.D. Wan Dalina ◽  
M. Mariatti ◽  
Soon Huat Tan ◽  
Z.A. Mohd Ishak ◽  
Abdul Rahman Mohamed
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
High Performance ◽  
Free Standing ◽  
Filtration Process ◽  
Different Types ◽  
Multi Walled Carbon Nanotubes ◽  
Triton X ◽  
Walled Carbon Nanotubes

Free-standing carbon nanotubes (CNTs) film known as buckypaper is a method used to address dispersion problems of CNTs. Unique properties of CNTs made the CNTs buckypaper to be considered as promising reinforcement materials in development of high-performance of nanocomposites. Buckypaper was fabricated by dispersing multi-walled carbon nanotubes (MWCNTs) in two different types of solution namely Triton X-100 and ethanol then followed by filtration process. In this study, MWCNTs loading and pressure used during filtration process were manipulated. The morphology, thermal and electrical conductivity of the buckypaper produced was studied.

Chemically Modified Multiwalled Carbon Nanotubes as an Additive for Supercapacitorsβ

2006 ◽  
Vol 963 ◽  
Author(s):  
Yong-Jung Kim ◽  
Yusuke Abe ◽  
Takashi Yanagiura ◽  
Masaaki Kitani ◽  
Tsuyoshi Kodama ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
High Performance ◽  
Rate Capability ◽  
Multiwalled Carbon ◽  
Super Capacitor ◽  
Chemically Modified ◽  
Multi Walled Carbon Nanotubes ◽  
Disordered Carbon ◽  
Walled Carbon Nanotubes

ABSTRACTThe incorporation of chemically modified multi-walled carbon nanotubes (MWNTs) have demonstrated, as an additive material to enhance the electrical conductivity, into the electrode gives rise to a highly improved rate capability of a super-capacitor. The preferential attack of potassium hydroxide on less disordered carbon results in the formation of high-performance MWNTs with increased surface area, electrical conductivity and sustained long tube morphology, simultaneously. It is envisaged that newly developed functional MWNTs will be utilized in various electrochemical systems, where high current is critically required.

scholarly journals Enhancement of Electrical Conductivity of Aluminum-Based Nanocomposite Produced by Spark Plasma Sintering

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1150
Author(s):  
Nicolás A. Ulloa-Castillo ◽  
Roberto Hernández-Maya ◽  
Jorge Islas-Urbano ◽  
Oscar Martínez-Romero ◽  
Emmanuel Segura-Cárdenas ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Spark Plasma Sintering ◽  
Experimental Tests ◽  
Powder Morphology ◽  
Plasma Sintering ◽  
Multi Walled Carbon Nanotubes ◽  
Spark Plasma ◽  
Ball Milling Technique ◽  
Walled Carbon Nanotubes

This article focuses on exploring how the electrical conductivity and densification properties of metallic samples made from aluminum (Al) powders reinforced with 0.5 wt % concentration of multi-walled carbon nanotubes (MWCNTs) and consolidated through spark plasma sintering (SPS) process are affected by the carbon nanotubes dispersion and the Al particles morphology. Experimental characterization tests performed by scanning electron microscopy (SEM) and by energy dispersive spectroscopy (EDS) show that the MWCNTs were uniformly ball-milled and dispersed in the Al surface particles, and undesirable phases were not observed in X-ray diffraction measurements. Furthermore, high densification parts and an improvement of about 40% in the electrical conductivity values were confirmed via experimental tests performed on the produced sintered samples. These results elucidate that modifying the powder morphology using the ball-milling technique to bond carbon nanotubes into the Al surface particles aids the ability to obtain highly dense parts with increasing electrical conductivity properties.

scholarly journals Synthesis, Characterization and Study of DC Electrical Conductivity of Poly[MWCNT/Imidoselenium] Composite

2019 ◽  
Author(s):  
Abeer O. Obeid ◽  
Fatma Al-Yusufy ◽  
Sama A Al-Aghbari ◽  
omar alshujaa ◽  
Yassin Gaber ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Selenium Dioxide ◽  
Chemical Functionalization ◽  
Dc Electrical Conductivity ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

<p>The chemical functionalization of amino multi-walled carbon nanotubes (MWCNT-NH<sub>2</sub>) by selenium dioxide (SeO<sub>2</sub>) was used to produce Poly [MWCNT/Imidoselenium] composite. The prepared poly-composite was characterized by FTIR, SEM, TEM, XRD, UV, DSC and TGA. The DC electrical conductivity of poly-composite was 4.3×10<sup>-4</sup> S/cm due to the interaction between the nanotubes. </p>

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