Effects of Molecular Weight and Annealing on Electrical Conductivity of Multi-Walled Carbon Nanotube/Polypropylene Composites

2010 ◽  
Vol 447-448 ◽  
pp. 619-623
Author(s):  
Yong Zheng Pan ◽  
Lin Li ◽  
Siew Hwa Chan ◽  
Jian Hong Zhao
Keyword(s):  
Electrical Conductivity ◽  
Molecular Weight ◽  
Mixing Process ◽  
Melt Mixing ◽  
Subsequent Formation ◽  
Polypropylene Composites ◽  
Post Annealing ◽  
Multi Walled Carbon Nanotube ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Composites of polypropylene (PP) and multi-walled carbon nanotubes (MWCNTs) were prepared by a micro melt mixing process. The molecular weight of PP was varied from 190,000 to 340,000 to examine its effects on the electrical conductivity. It has been discovered that a significant enhancement of electrical conductivity could be achieved by a thermal post annealing process above the melting temperature of PP. Factors such as annealing time, temperature, viscosity of PP, and content of MWCNTs all affected the enhancement of electrical conductivity. Re-aggregation of MWCNTs and the subsequent formation of MWCNT networks during annealing are considered to be the main reasons for the quick enhancement of electrical conductivity. The observed effect of molecular weight of PP on the enhancement of electrical conductivity suggested that the enhancement process could be controlled by diffusion of MWCNTs.

Effects of incorporation of polyester on the electrical resistivity of polycarbonate/multi-walled carbon nanotube nanocomposite

2018 ◽  
Vol 53 (10) ◽  
pp. 1291-1298 ◽  
Author(s):  
Hee Young Lee ◽  
Heidy Cruz ◽  
Younggon Son
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Polybutylene Terephthalate ◽  
Melt Mixing ◽  
Crystal Polymer ◽  
Multi Walled Carbon Nanotube ◽  
Random Block ◽  
Multi Walled Carbon Nanotubes ◽  
Injection Molded ◽  
Walled Carbon Nanotubes

In this work, we present the effect of incorporation of polyester on the electrical properties of injection-molded polycarbonate/multi-walled carbon nanotube nanocomposites. The study was conducted by melt-mixing polycarbonate, multi-walled carbon nanotube, and three types of polyesters: polybutylene terephthalate, polyethylene terephthalate, and liquid crystal polymer. It was found that the volume resistivities of injection-molded composites containing 2 phr polyester significantly decreased because of the transesterification reaction between the polycarbonate and polyester. The resulting polycarbonate-polyester random block copolymer kept the conductive networks intact because of the preferential affinity of multi-walled carbon nanotubes with polyester. This study showed that incorporating polyester with polycarbonate–multi-walled carbon nanotube increases the electrical conductivity of injection-molded polycarbonate/multi-walled carbon nanotube nanocomposites to a great extent.

Characterization and modeling of the effective electrical conductivity of a carbon nanotube/polymer composite containing chain-structured ferromagnetic particles

2016 ◽  
Vol 51 (2) ◽  
pp. 171-178 ◽  
Author(s):  
Sung-Hwan Jang ◽  
Huiming Yin
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Chain Model ◽  
Sensing Applications ◽  
Effective Electrical Conductivity ◽  
Multi Walled Carbon Nanotube ◽  
The Matrix ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Ferromagnetic Particles

The effective electrical conductivity of multi-walled carbon nanotube/polydimethylsiloxane composites with chain-structured ferromagnetic particles has been investigated by experiments and micromechanics-based modeling. A multi-scale modeling approach is used to consider different size of fillers of multi-walled carbon nanotubes and particles as well as their distribution in the matrix. At nanoscale, for multi-walled carbon nanotube/polydimethylsiloxane composite, eight-chain model and influence of waviness of multi-walled carbon nanotube are considered to render an effective electrical conductivity. At microscale, ferromagnetic particles are aligned in the matrix made of the multi-walled carbon nanotube/polydimethylsiloxane composite, and an analytical model is established based on representative volume element. The influence of inter-particle distance is evaluated. The proposed analytic results agree well with the experimental results. The present model can be a useful tool for design and analysis of these composites for sensing applications considering their percolation threshold and overall electrical conductivity.

Fabrication and characterization of MWCNT/natural Azerbaijani bentonite electroconductive ceramic composites

2019 ◽  
Vol 53 (26-27) ◽  
pp. 3909-3923 ◽  
Author(s):  
Asgar Huseynov ◽  
Aydin Israfilov ◽  
Samira Mammadova ◽  
Sevda Abdullayeva ◽  
Sergey Sokolov ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Ceramic Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multi Walled Carbon Nanotube ◽  
Multi Walled Carbon Nanotubes ◽  
Bentonite Clays ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotubes have been synthesized by Aerosol-Chemical Vapor Deposition method. Carbon nanotubes firstly have been used as filler in affordable and prevalent natural Azerbaijani bentonite clays for fabrication electroconductive ceramic composites. In this paper, multi-walled carbon nanotubes/natural Azerbaijani bentonite ceramic composites were prepared by two-factor mechanical method and followed by calcination at 1050℃ in an inert atmosphere. The ceramic composites were characterized by scanning electron microscope, atomic force microscope, X-ray diffraction and thermogravimetric-differential-thermal analysis. X-ray diffraction analysis confirmed the presence of two principal components – multi-walled carbon nanotube and bentonite in composites. From the thermogravimetric-differential-thermal data, it was revealed that multi-walled carbon nanotube/ bentonite ceramic composites demonstrate thermo-oxidative stability up to 580–640℃. Scanning electron microscope images demonstrated a sufficiently high dispersibility of carbon nanotubes and satisfactory homogeneity in the composites. Experimental results demonstrated that by increasing the mass fraction of multi-walled carbon nanotubes from 1% to 8% in multi-walled carbon nanotube/bentonite ceramic composites, the electrical conductivity enhances substantially. The enhancement of electrical conductivity of the composites explained the mass fraction of multi-walled carbon nanotubes, as well as the uniform dispersion of multi-walled carbon nanotubes in the bentonite clays. Compared with other 8% multi-walled carbon nanotubes/bentonite ceramic composites, the electrical conductivity of heptane-multi-walled carbon nanotube/Gobu bentonite (σ = 397 S·m−1) and heptane-multi-walled carbon nanotubes/Atyali (σ = 305 S·m−1) composites is 2–5 times higher than the conductivity of composites obtained with cyclohexane carbon nanotubes- cyclohexane-multi-walled carbon nanotube/Atyali (σ = 78 S·m−1), cyclohexane-multi-walled carbon nanotube/Gobu (σ = 111,5 S·m−1). These results can be explained with the structure, the number of layers, purity and diameter distribution, as well as the type and amount of defects in internal and external layers of Hep-multi-walled carbon nanotubes which cause better dispersion in bentonite clays. Due to the high conductivity and high temperature stability, these composites can be used as promising material for fabrication heating elements, electrodes, substrates for microelectronic devices, etc.

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 Fabrication of carbon nanotube-reinforced mortar specimens: evaluation of mechanical and pressure-sensitive properties

2018 ◽  
Vol 188 ◽  
pp. 01019 ◽  
Author(s):  
Evangelia K. Karaxi ◽  
Irene A. Kanellopoulou ◽  
Anna Karatza ◽  
Ioannis A. Kartsonakis ◽  
Costas A. Charitidis
Keyword(s):  
Cementitious Composites ◽  
Mixing Process ◽  
Mechanical And Electrical Properties ◽  
Pressure Sensitive ◽  
Polar Media ◽  
Significant Research ◽  
Multi Walled Carbon Nanotubes ◽  
Carbon Based Nanomaterials ◽  
Walled Carbon Nanotubes ◽  
Carbon Based

Carbon-based nanomaterials are promising reinforcing elements for the development of “smart” self-sensing cementitious composites due to their exceptional mechanical and electrical properties. Significant research efforts have been committed on the synthesis of cement-based composite materials reinforced with carbonaceous nanostructures, covering every aspect of the production process (type of nanomaterial, mixing process, electrode type, measurement methods etc.). In this study, the aim is to develop a well-defined repeatable procedure for the fabrication as well as the evaluation of pressure-sensitive properties of intrinsically self-sensing cementitious composites incorporating carbon- based nanomaterials. Highly functionalized multi-walled carbon nanotubes with increased dispersibility in polar media were used in the development of advanced reinforced mortar specimens which increased their mechanical properties and provided repeatable pressure-sensitive properties.

Multi-Walled Carbon Nanotubes as Electrocatalyst Supports for H2O2 Reduction Reaction

2013 ◽  
Vol 860-863 ◽  
pp. 831-834
Author(s):  
Dan Zheng ◽  
Ting Fang Yang ◽  
Zhang Fei Guo
Keyword(s):  
Cyclic Voltammetry Curve ◽  
Chemical Reduction ◽  
Reduction Reaction ◽  
Carbon Substrate ◽  
Acid Media ◽  
Multi Walled Carbon Nanotube ◽  
Multi Walled Carbon Nanotubes ◽  
Current Densities ◽  
Reaction Activation Energy ◽  
Walled Carbon Nanotubes

This work studies the use of Multi-walled carbon nanotube (MWCNT) as catalyst supports for H2O2 electro-reduction in acid media. Using impregnation-chemical reduction method, we prepared Pt-Ag/CNTs, Pt-Co/CNTs, Pt-Ag/C and Pt-Co/C nanocatalysts. Four catalysts were analyzed by XRD and TEM. Their electrochemical performance was studied via cyclic voltammetry curve. The results show that: the nanoparticles have a better dispersion on CNTs substrate than on XC-72 carbon substrate. Comparing with Pt-Ag and Pt-Co on XC-72 carbon substrate, the H2O2 reduction reaction activation energy of catalysts on CNTs substrate is bigger, and the peak current densities of catalysts on CNTs substrate are larger than that on XC-72 carbon.

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>

Highly sensitive compression sensors using three-dimensional printed polydimethylsiloxane/carbon nanotube nanocomposites

2019 ◽  
Vol 30 (8) ◽  
pp. 1216-1224 ◽  
Author(s):  
Mohammad Charara ◽  
Mohammad Abshirini ◽  
Mrinal C Saha ◽  
M Cengiz Altan ◽  
Yingtao Liu
Keyword(s):  
Carbon Nanotubes ◽  
Electron Microscope ◽  
Carbon Nanotube ◽  
Scanning Electron Microscope ◽  
Three Dimensional ◽  
Multi Walled Carbon Nanotube ◽  
Highly Sensitive ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

This article presents three-dimensional printed and highly sensitive polydimethylsiloxane/multi-walled carbon nanotube sensors for compressive strain and pressure measurements. An electrically conductive polydimethylsiloxane/multi-walled carbon nanotube nanocomposite is developed to three-dimensional print compression sensors in a freestanding and layer-by-layer manner. The dispersion of multi-walled carbon nanotubes in polydimethylsiloxane allows the uncured nanocomposite to stand freely without any support throughout the printing process. The cross section of the compression sensors is examined under scanning electron microscope to identify the microstructure of nanocomposites, revealing good dispersion of multi-walled carbon nanotubes within the polydimethylsiloxane matrix. The sensor’s sensitivity was characterized under cyclic compression loading at various max strains, showing an especially high sensitivity at lower strains. The sensing capability of the three-dimensional printed nanocomposites shows minimum variation at various applied strain rates, indicating its versatile potential in a wide range of applications. Cyclic tests under compressive loading for over 8 h demonstrate that the long-term sensing performance is consistent. Finally, in situ micromechanical compressive tests under scanning electron microscope validated the sensor’s piezoresistive mechanism, showing the rearrangement, reorientation, and bending of the multi-walled carbon nanotubes under compressive loads, were the main reasons that lead to the piezoresistive sensing capabilities in the three-dimensional printed nanocomposites.

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