Electrical Conduction in Carbon Black Composites

1986 ◽  
Vol 59 (3) ◽  
pp. 432-454 ◽  
Author(s):  
Avrom I. Medalia
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Electrical Conduction ◽  
Electromagnetic Interference ◽  
Physical Processes ◽  
Intrinsic Conductivity ◽  
Dominant Process

Abstract Electrical conductivity is important in many rubber and plastic compounds including antistatic applications, wire and cable sheathing, and shielding against electromagnetic interference (EMI). Elastomers and plastics are insulators (dielectrics) to which conductivity is imparted by addition of a finely divided or colloidal filler of high intrinsic conductivity, such as carbon black. Over the years, there has developed a sizable body of information regarding measurement of conductivity, and the factors which affect it in such compounds or composites. With regard to the physical processes involved in the conduction of electricity, various mechanisms have been proposed by various authors. It appears that many physical processes can be involved and that the dominant process depends upon the composition of the composite and the conditions of measurement. The purpose of this review is to survey the proposed mechanisms of conduction in composites of carbon black and nonconductive polymers, taking special note of recent theoretical advances, and to examine the effects of the properties of the carbon black and the composition of the composite.

Investigation of Abrasion of Nitrile Rubber

1984 ◽  
Vol 57 (4) ◽  
pp. 769-778 ◽  
Author(s):  
S. W. Zhang
Keyword(s):  
Steady State ◽  
Carbon Black ◽  
Crack Growth ◽  
Unsteady State ◽  
Small Particles ◽  
Physical Processes ◽  
Wear Rates ◽  
Rubber Compounds ◽  
Dominant Process ◽  
Particulate Wear

Abstract Abrasion of NBR appears as a dry (particulate) wear, similar to unfilled BR, NR, and SBR, and filled BR. The abraded surface seems textured on two scales: that of the ridges of the abrasion pattern and that of small particles of debris. The formation of macroridges on filled and unfilled NBR appears to involve two distinct ridges one formed after the other. First, fine and tightly spaced primary ridges, followed by rough and sparsely spaced secondary ridges. The abrasion pattern on unfilled NBR is relatively stable once steady state has been reached and the pattern has been fully developed. As for the filled NBR, both the scale and roughness of the secondary ridges are uneven, even if steady state has been reached completely. Wear rates of filled and unfilled NBR have been found to be proportional to an exponent n of the applied frictional work. The unsteady state rates of wear were also somewhat dependent on the number of revolutions of the test wheel. Both the proportionality coefficient k and exponent n are dependent upon the composition and also upon the wear state. The exponent n for unfilled NBR is greater than that for filled NBR, and for the unsteady state it is greater than that for steady state. Reversals in the relative rates of wear between filled and unfilled NBR are also observed at different severities of abrasion. This phenomenon perhaps reflects a competition between two different physical processes: crack growth and rupture of tongue tip. The dominant process may be crack growth at low severities of wear and rupture of the tongue tip at high severities of wear. Therefore, the fact that, at high severities, carbon black markedly reduces the rates of abrasion might be attributed to the tensile strength gain of rubber compounds due to reinforcement by carbon black.

Electrical conductivity and rheological properties of carbon black based conductive polymer composites prior to and after annealing

2021 ◽  
pp. 096739112110012
Author(s):  
Qingsen Gao ◽  
Jingguang Liu ◽  
Xianhu Liu
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Percolation Threshold ◽  
Rheological Properties ◽  
Network Formation ◽  
Loss Modulus ◽  
Conductive Polymer ◽  
Complex Viscosity ◽  
Electrical Percolation ◽  
Electrical Percolation Threshold

The effect of annealing on the electrical and rheological properties of polymer (poly (methyl methacrylate) (PMMA) and polystyrene (PS)) composites filled with carbon black (CB) was investigated. For a composite with CB content near the electrical percolation threshold, the formation of conductive pathways during annealing has a significant impact on electrical conductivity, complex viscosity, storage modulus and loss modulus. For the annealed samples, a reduction in the electrical and rheological percolation threshold was observed. Moreover, a simple model is proposed to explain these behaviors. This finding emphasizes the differences in network formation with respect to electrical or rheological properties as both properties belong to different physical origins.

Investigation of Electromagnetic Interference Shielding Effectiveness of Cement-Based Composites Filled with Carbon Materials

2010 ◽  
Vol 168-170 ◽  
pp. 1021-1024
Author(s):  
Guo Xuan Xiong ◽  
Zhi Bin Zhang ◽  
Min Deng ◽  
Yu Fen Zhou
Keyword(s):  
Carbon Fiber ◽  
Carbon Black ◽  
Electromagnetic Interference ◽  
Carbon Materials ◽  
Shielding Effectiveness ◽  
Nano Carbon ◽  
Electromagnetic Interference Shielding Effectiveness ◽  
Carbon Nano Tube ◽  
Relationship Of ◽  
The Relationship

The cement-based composite shielding materials filled with carbon materials such as ordinary carbon materials (graphite, coke and carbon black), carbon fiber and nano-carbon materials (carbon nano-tube and nano-carbon black) were prepared. The relationship of conductivity and shielding effectiveness in a frequency range of 100 KHz~1.5 GHz was studied. The electric properties of cement-based composites filled with carbon fiber is better than other carbon materials. With the contents of carbon fiber of 5.vol%, the average shielding effectiveness is about 37 dB and the maximum shielding effectiveness reaches 40 dB.

Dual percolations of electrical conductivity and electromagnetic interference shielding in progressively agglomerated CNT/polymer nanocomposites

2021 ◽  
pp. 108128652110214
Author(s):  
Xiaodong Xia ◽  
George J. Weng
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Polymer Nanocomposites ◽  
Electromagnetic Interference ◽  
Effective Medium Theory ◽  
Scale Model ◽  
Shielding Effectiveness ◽  
Emi Shielding

Recent experiments have revealed two distinct percolation phenomena in carbon nanotube (CNT)/polymer nanocomposites: one is associated with the electrical conductivity and the other is with the electromagnetic interference (EMI) shielding. At present, however, no theories seem to exist that can simultaneously predict their percolation thresholds and the associated conductivity and EMI curves. In this work, we present an effective-medium theory with electrical and magnetic interface effects to calculate the overall conductivity of a generally agglomerated nanocomposite and invoke a solution to Maxwell’s equations to calculate the EMI shielding effectiveness. In this process, two complex quantities, the complex electrical conductivity and complex magnetic permeability, are adopted as the homogenization parameters, and a two-scale model with CNT-rich and CNT-poor regions is utilized to depict the progressive formation of CNT agglomeration. We demonstrated that there is indeed a clear existence of two separate percolative behaviors and showed that, consistent with the experimental data of poly-L-lactic acid (PLLA)/multi-walled carbon nanotube (MWCNT) nanocomposites, the electrical percolation threshold is lower than the EMI shielding percolation threshold. The predicted conductivity and EMI shielding curves are also in close agreement with experimental data. We further disclosed that the percolative behavior of EMI shielding in the overall CNT/polymer nanocomposite can be illustrated by the establishment of connective filler networks in the CNT-poor region. It is believed that the present research can provide directions for the design of CNT/polymer nanocomposites in the EMI shielding components.

scholarly journals Multi-material braids for multifunctional laminates: conductive through-thickness reinforcement

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Caroline O’Keeffe ◽  
Laura Rhian Pickard ◽  
Juan Cao ◽  
Giuliano Allegri ◽  
Ivana K. Partridge ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Carbon Fibre ◽  
Electromagnetic Interference ◽  
Design Tool ◽  
Electrically Conductive ◽  
Current Collection ◽  
Wide Range ◽  
Predictive Design ◽  
The Right ◽  
Metal Wires

AbstractConventional carbon fibre laminates are known to be moderately electrically conductive in-plane, but have a poor through-thickness conductivity. This poses a problem for functionality aspects that are of increasing importance to industry, such as sensing, current collection, inductive/resistive heating, electromagnetic interference (EMI) shielding, etc. This restriction is of course more pronounced for non-conductive composite reinforcements such as glass, organic or natural fibres. Among various solutions to boost through-thickness electrical conductivity, tufting with hybrid micro-braided metal-carbon fibre yarns is one of the most promising. As a well-characterised method of through thickness reinforcement, tufting is easily implementable in a manufacturing environment. The hybridisation of materials in the braid promotes the resilience and integrity of yarns, while integrating metal wires opens up a wide range of multifunctional applications. Many configurations can be produced by varying braid patterns and the constituting yarns/wires. A predictive design tool is therefore necessary to select the right material configuration for the desired functional and structural performance. This paper suggests a fast and robust method for generating finite-element models of the braids, validates the prediction of micro-architecture and electrical conductivity, and demonstrates successful manufacturing of composites enhanced with braided tufts.

Investigate of Electrical Conductivity of Shape-Memory Polymer Filled with Carbon Black

2008 ◽  
Vol 47-50 ◽  
pp. 714-717 ◽  
Author(s):  
Xin Lan ◽  
Jin Song Leng ◽  
Yan Ju Liu ◽  
Shan Yi Du
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Shape Memory ◽  
Shape Recovery ◽  
Volume Fraction ◽  
Shape Memory Polymer ◽  
Recovery Process ◽  
Thermomechanical Properties ◽  
Electrically Conductive ◽  
New System

A new system of thermoset styrene-based shape-memory polymer (SMP) filled with carbon black (CB) is investigated. To realize the electroactive stimuli of SMP, the electrical conductivity of SMP filled with various amounts of CB is characterized. The percolation threshold of electrically conductive SMP filled with CB is about 3% (volume fraction of CB), which is much lower than many other electrically conductive polymers. When applying a voltage of 30V, the shape recovery process of SMP/CB(10 vol%) can be realized in about 100s. In addition, the thermomechanical properties are also characterized by differential scanning calorimetery (DSC).

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