Electrical conductivity of vapor-grown carbon fiber/thermoplastic composites

2001 ◽  
Vol 16 (6) ◽  
pp. 1668-1674 ◽  
Author(s):  
Ioana C. Finegan ◽  
Gary G. Tibbetts
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Carbon Fiber ◽  
Conducting Polymers ◽  
Radio Frequency ◽  
Percolation Threshold ◽  
Thermoplastic Composites ◽  
Radio Frequency Interference ◽  
Static Discharge

Conducting polymers are required for applications such as radio frequency interference shielding, primerless electrostatic painting, and static discharge. We have used vapor-grown carbon fiber (VGCF) as an additive to investigate conducting thermoplastics for these applications. The electrical properties of VGCF/polypropylene (PP) and VGCF/nylon composites are very attractive compared with those provided by other conventional conducting additives. Because of the low diameter of the VGCF used, the onset of conductivity (percolation threshold) can be below 3 vol%. Because of the highly conductive nature of the fibers, particularly after a graphitization step, the composites can reach resistivities as low as 0.15 Ω cm.

scholarly journals Influence of Carbon Fiber Incorporation on Electrical Conductivity of Cement Composites

2020 ◽  
Vol 10 (24) ◽  
pp. 8993
Author(s):  
Ilhwan You ◽  
Seung-Jung Lee ◽  
Goangseup Zi ◽  
Daehyun Lim
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Carbon Fiber ◽  
Percolation Threshold ◽  
Cement Composite ◽  
Electrode Spacing ◽  
Cement Composites ◽  
Different Types ◽  
The Difference

This study investigated the effects of carbon fiber (CF) length, electrode spacing, and probe configuration on the electrical conductivity of cement composites. Accordingly, 57 different types of samples were prepared, considering three different CF lengths, five different CF contents, three different electrode spacings, and two different probe configurations. This research found that the influence of CF length on the electrical resistivity of cement composite depends electrode spacing. For the cement composite with wide electrode spacing of 40 mm, its resistivity decreased as increasing CF length as in the previous study. However, when the electrode spacing is 10 mm, which is narrow (10 mm), the resistivity of the cement composite rather increased with increasing CF length. The results implied that when an electrode is designed for the cement composite incorporating CF, the CF length should be short compared to the electrode spacing. The percolation threshold of CF measured by the two-probe configuration was 2% or more. This is higher than that measured by the four-probe configuration (1%). At a lower CF content than 2%, the two-probe configuration gave higher resistivity of the cement composite than the four-probe configuration. However, the difference coming from the different probe configurations was marginal as increasing the CF content.

Laser-Induced Ionization of Atoms in a Power-Modulated Inductively Coupled Plasma

1992 ◽  
Vol 46 (8) ◽  
pp. 1217-1222 ◽  
Author(s):  
Gregory C. Turk ◽  
Lijian Yu ◽  
Robert L. Waiters ◽  
John C. Travis
Keyword(s):  
Electrical Conductivity ◽  
Radio Frequency ◽  
Inductively Coupled Plasma ◽  
Resonance Ionization ◽  
Radio Frequency Interference ◽  
Conductivity Measurements ◽  
Resonance Ionization Spectroscopy ◽  
Inductively Coupled ◽  
Excited Atoms ◽  
Plasma Background

Laser-induced ionization of atoms has been detected in a power-modulated inductively coupled plasma. The measurement is made 1.4 ms after complete interruption of the 40-MHz power to a 400-W plasma. Electrical conductivity measurements between probe electrodes in the plasma during the power-off cycle have been made, demonstrating the decay in plasma background ion/electron concentrations which makes detection of laser-induced ionization possible. Radio-frequency interference from the ICP on the ionization detection electronics is also avoided by this approach. The primary mode of laser-induced ionization was photoionization of the laser-excited atoms, i.e., resonance ionization spectroscopy (RIS). Detection limits of 80 µg Fe/L and 20 µg Ga/L were achieved.

Percolation and Electrical Conductivity Modeling of Novel Microstructured Insulator-Conductor Nanocomposites Fabricated from PMMA and ATO

2014 ◽  
Vol 1692 ◽  
Author(s):  
Youngho Jin ◽  
Rosario A. Gerhardt
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Percolation Threshold ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Conductive Filler ◽  
Molding Pressure ◽  
Shape Transformation ◽  
Element Analysis ◽  
3D Network

ABSTRACTThe electrical conductivity of insulating polymer matrix composites undergoes radical increase at a certain concentration of conductive filler, which is known as the percolation threshold. Polymer matrix conductive nanocomposites were fabricated by compression molding the mechanically mixed poly (methyl methacrylate) (PMMA) and antimony tin oxide (ATO) nanoparticles, as has been done with other polymer composites before. The electrical conductivity of PMMA/ATO nanocomposites increased by several orders of magnitude at a small concentration of ATO (∼ 0.27 vol %). The continuous 3D network like distribution of ATO nanoparticles contributed to this percolation at subcritical filler concentrations. The effects of processing parameters on these unique microstructures and electrical properties were investigated. The tetrakaidecahedron-like microstructure was observed by scanning electron microscopy (SEM) and was found to be affected by the molding pressure, temperature and amount of nanoparticles. The viscoelastic flow of matrix under the optimum processing conditions allowed the shape transformation of PMMA into space filling polyhedra and an ordered distribution of ATO nanoparticles along the sharp edges of the PMMA. Parametric finite element analysis was performed to model this unique microstructure-driven percolation. The 2D simplified model was generated in AC/DC frequency domain mode in COMSOL Multiphysics® to solve the effects of ordered distribution of conductive nanoparticles on the electrical properties of the composite. There was excellent agreement between experimental and simulated values of electrical conductivity and percolation concentration. This model can be used to predict percolation threshold and electrical properties for any types of composite systems containing insulating matrix and conductive fillers that can form this unique microstructure.

Mechanical and Electrical Properties of Graphite/Carbon Fiber/Phenolic Resin Composite

2011 ◽  
Vol 418-420 ◽  
pp. 1452-1455
Author(s):  
Mi Dan Li ◽  
Dong Mei Liu
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Phenolic Resin ◽  
Resin Composite ◽  
Low Carbon ◽  
Mechanical Mixing ◽  
Mechanical And Electrical Properties ◽  
Resin Loading

Composites made of phenolic resin filled with natural graphite platelets and carbon fibers are fabricated by mechanical mixing, followed by compression molding. The flexural strength and electrical conductivity of composite are analyzed to determine the influence of phenolic resin and carbon fiber on mechanical and electrical properties. It is found that there is a marked dependence of the electrical conductivity and flexural strength on phenolic resin content. The electrical conductivity decreases and flexural strength increases with the increasing of phenolic resin loading. The presence of carbon fiber helps improve the flexural strength of composite such that 4 wt% CF increases the flexural strength of composite about 90%. However, an excess amount of carbon fiber reduces the flexural strength due to poor dispersion of carbon fiber in composite. The result also shows that the addition of carbon fiber exhibits a slight effect on the electrical conductivity of composite at low carbon fiber loadings.

Assessment on the Electrical Conductivity of Additive Fillers into Carbon Fiber-Cement Based Composites

2011 ◽  
Vol 492 ◽  
pp. 185-188 ◽  
Author(s):  
Jun Jie Qin ◽  
Wu Yao ◽  
Jun Qing Zuo ◽  
Hai Yong Cao
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Carbon Fiber ◽  
Percolation Threshold ◽  
Electrical Conduction ◽  
Cement Matrix ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

This paper gives an assessment on the electrical conductivity of different additive fillers (graphite, multi-walled carbon nanotubes) into carbon fiber-cement based composites (CFRC). Results show that cement matrix containing 0.4% carbon fiber (CF) and 0.5% multi-walled carbon nanotubes (MWCNTs) exhibits an excellent electrical conductivity of 33.65Ω·cm. When the content of CF is below the percolation threshold (0.4% CF), adding graphite is beneficial to the electrical conduction of CFRC, which has a tremendous drift from 3991.44Ω·cm to 524.33Ω·cm as the content of graphite varies from 0% to 30%. However, when the content of CF is above the percolation threshold, adding graphite makes no advantages in the electrical conductivity of CFRC because of leading to a porosity rising. MWCNTs are useful conductive constituents for CFRC and can increase electrical conductivity by two orders of magnitude. However, excessive adding MWCNTs into CFRC will have a rapid increase of electrical resistivity on the contrary.

Electrical properties of anisotropic graphene/PDMS composites induced by aligned ferromagnetic particles

2020 ◽  
pp. 1045389X2096986
Author(s):  
Shuai Dong ◽  
Shiwei Chen ◽  
Bin Li ◽  
Xiaojie Wang
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Percolation Threshold ◽  
Conductive Polymer ◽  
Critical Value ◽  
Iron Particles ◽  
Mechanical And Electrical Properties ◽  
Anisotropic Structures ◽  
Potential Applications

Graphene nanoplate (GNP) is a two-dimensional plate-like carbon material with high aspect ratio and excellent electrical conductivity. It is one of the most commonly used fillers for conductive polymer composites (CPCs), which have potential applications in flexible electrodes and sensors. The electrical properties of the CPCs particularly depend on the microstructure of GNP networks. The electrical conductivity of the CPCs leaps in several magnitude levels when the graphene concentration reaches a critical value, which is defined as the percolation threshold. For ordinary isotropic CPCs, the percolation threshold is relatively high, which leads to inferior performance with poor mechanical and electrical properties. Aligning the graphene plates is an effective method to reduce the percolation threshold of the CPCs. Carbonyl iron particles (CIPs) are easily aligned to form chain-like structures when a magnetic field is applied. In this work, CIPs and GNPs are mixed with polydimethylsiloxane (PDMS), and the hybrid is cured under a magnetic field of 0.5 T. The alignment of CIPs induces the GNPs in the PDMS to orientate in a certain direction under the applied magnetic field generating anisotropic structures. Both isotropic and anisotropic structured GNPs/PDMS composites are prepared with various GNP concentrations. The microstructure and electrical conductivity of the GNPs/PDMS composites are investigated by experimental methods. It is found that anisotropic graphene networks are formed and the percolation threshold of the anisotropic composites is 0.15 vol%, compared to that of the isotropic composites which is 0.85 vol%. The alignment of GNPs significantly reduces the percolation threshold. Furthermore, a plate lattice model is proposed to reveal the effect of the alignment of GNPs on the formation of conductive networks. With the increase of the alignment degree of GNPs, the percolation threshold decreases significantly, which is consistent with the experimental results.

Synergistic effects of hybrid conductive fillers on the electrical properties of carbon fiber pultruded polypropylene/polycarbonate composites prepared by injection molding

2016 ◽  
Vol 51 (7) ◽  
pp. 1005-1017 ◽  
Author(s):  
Myung Geun Jang ◽  
Choonglai Cho ◽  
Woo Nyon Kim
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Carbon Fiber ◽  
Injection Molding ◽  
Electromagnetic Interference ◽  
Synergistic Effects ◽  
Shielding Effectiveness ◽  
Electromagnetic Interference Shielding ◽  
Preparation Methods ◽  
Electromagnetic Interference Shielding Effectiveness

In this study, the effects of filler characteristics and composite preparation methods on the morphology, mechanical property, electrical conductivity, and electromagnetic interference shielding effectiveness of the polypropylene/polycarbonate (70/30, wt%)/hybrid conductive filler composites were investigated. Nickel-coated carbon fiber (NCCF) was used as main filler and TiO2, multi-walled carbon nanotube, and graphite were used as second fillers in the composites. The pultruded NCCF/polypropylene composite was used in the preparation of the polypropylene/polycarbonate/NCCF/second filler composites. The electrical conductivity and electromagnetic interference shielding effectiveness of the polypropylene/polycarbonate/NCCF/second filler composites were compared with the type of second filler. The superior value of electromagnetic interference shielding effectiveness was observed to be 51.6 dB (decibel) when the hybrid fillers such as NCCF (5.2 vol% or 20 wt%) and TiO2 (1.2 vol% or 5 wt%) were added in the polypropylene/polycarbonate (70/30) composite. The electrical properties of the polypropylene/polycarbonate (70/30)/NCCF/TiO2 composites was compared with the composite preparation methods, which were injection molding and screw extrusion. The results suggested that fiber length of the NCCF affected significantly to the electrical conductivity and electromagnetic interference shielding effectiveness of the polypropylene/polycarbonate (70/30)/NCCF/TiO2 composites.

Study on the Electrical Properties of CNT/Carbon Fiber Reinforced Composite

2015 ◽  
Vol 813 ◽  
pp. 315-322
Author(s):  
Yan Li ◽  
Meng Ma
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Carbon Fiber ◽  
Volume Fraction ◽  
Fiber Direction ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Reinforced Composite ◽  
Current Path ◽  
Carbon Fiber Reinforced

The effects of fiber orientation and volume fraction on electrical conductivity of unidirectional carbon fiber reinforced polymer (CFRP) were investigated. The unidirectional CFRP shows strong anisotropy in electrical properties. Composites with higher fiber volume fraction possess higher electrical conductivity, since the fibers are the only current path in the composites. Additionally, carbon nanotubes (CNTs) were mixed into the resin by high-pressure microfluidizer to improve the electrical properties of the composites. Results show that the electrical conductivity of the polymer matrix has been dramatically improved. The conductivity of CNTs modified CFRP composites is improved along fiber direction, while it remains at the same level in the transverse to fiber direction.

scholarly journals Quasi-Static Multifunctional Characterization of 3D-Printed Carbon Fiber Composites for Compressive-Electrical Properties

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 328
Author(s):  
Ritesh Ghimire ◽  
Frank Liou
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Carbon Fiber ◽  
Fiber Composites ◽  
New Method ◽  
Carbon Fiber Composites ◽  
Continuous Carbon Fiber ◽  
3D Printed ◽  
Multifunctional Properties

Multifunctional carbon fiber composites provide promising results such as high strength-to-weight ratio, thermal and electrical conductivity, high-intensity radiated field, etc. for aerospace applications. Tailoring the electrical and structural properties of 3D-printed composites is the critical step for multifunctional performance. This paper presents a novel method for evaluating the effects of the coating material system on the continuous carbon fiber strand on the multifunctional properties of 3D-printed composites and the material’s microstructure. A new method was proposed for the quasi-static characterization of the Compressive-Electrical properties on the additively manufactured continuous carbon fiber solid laminate composites. In this paper, compressive and electrical conductivity tests were simultaneously conducted on the 3D-printed test coupons at ambient temperature. This new method modified the existing method of addressing monofunctional carbon fiber composites by combining the monofunctionality of two or more material systems to achieve the multifunctional performance on the same component, thereby reducing the significant weight. The quasi-static multifunctional properties reported a maximum compressive load of 4370 N, ultimate compressive strength of 136 MPa, and 61.2 G Ohms of electrical resistance. The presented method will significantly reduce weight and potentially replace the bulky electrical wires in spacecraft, unmanned aircraft systems (UAS), and aircraft.

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