Research on Conductive Property of Carbon Fiber/Carbon Black-Filled Cement-Based Composites

2012 ◽  
Vol 182-183 ◽  
pp. 144-147 ◽  
Author(s):  
Yan Ting Du ◽  
Ran Ran Zhao ◽  
Jin Qiu Dong
Keyword(s):  
Carbon Fiber ◽  
Carbon Black ◽  
Percolation Theory ◽  
Volume Fraction ◽  
Fixed Carbon ◽  
Total Volume Fraction ◽  
Conductive Property ◽  
Conductive Particles ◽  
Percolation Phenomenon ◽  
Lower Resistivity

Electrical conductive carbon-modified cement-based composites are important multi-functional structural material. Double compounding carbon fiber and carbon black into cement-based material can improve the electrical conductive property of cement-based composites. In this paper, the influences of carbon fiber ratio and total volume fraction of carbon components on the resistivity of cement-based composites are investigated. The results show that both carbon fiber ratio and total volume fraction have great effect on the conductive behavior of carbon-modified cement-based material. At a fixed carbon fiber ratio, with the increase of total volume fraction, the resistivity of cement-based composites drops down dramatically and shows obvious percolation phenomenon. The reason is that with more and more conductive particles and fibers added into the cement material, the conductive components connect with each other gradually and at certain point reach the percolation threshold. At a fixed total volume fraction, the resistivity drops down with the increase of carbon fiber ratio. This is because that the carbon fiber has larger aspect ratio than carbon black, so carbon fiber could get lower resistivity with the same dosage according to the percolation theory. Finally, the results show that with 0.5 carbon fiber ratio and 2% total volume fraction the carbon-modified cement-based composites have relatively low resistivity, high workability and high compressive strength.

Percolation Phenomenon in Thermal Conductivity of Carbon Black Filled Rubber and Morphology

2010 ◽  
Vol 146-147 ◽  
pp. 575-580
Author(s):  
Jun Ping Song
Keyword(s):  
Thermal Conductivity ◽  
Carbon Black ◽  
Natural Rubber ◽  
Percolation Threshold ◽  
Volume Fraction ◽  
Graphitized Carbon Black ◽  
Rubber Matrix ◽  
Rubber Composites ◽  
Percolation Behavior ◽  
Percolation Phenomenon

A kind of graphitized carbon black 40B2 was incorporated in natural rubber matrix and vulcanizates were prepared. The content of carbon black varied from 4 to 100phr for 100phr of natural rubber. Thermal conductivity of the CB/rubber composites was studied as a function of CB loadings and temperature. TEM and SEM were employed to explore the morphology of the carbon black and the composites. It was found that percolation phenomenon existed in thermal conductivity of CB/rubber composites at different filler loadings, which was much similar with percolation behavior in electrical conductivity properties of many composites, and the percolation threshold was about 13.63%. The influence of temperature on thermal conductivity was more obviously within the region from the percolation threshold to the volume fraction of 26.2%.However, no great effect could be found on the percolation behavior of the composites in thermal conductivity. The result of TEM indicated that the mean size of CB particles was about 25nm, the maximum size of CB aggregates was about 125nm, and the CB aggregates were multichain in shape. The results of SEM showed that the distribution of CB differed at different filler loadings. Before the percolation threshold, the CB aggregates existed isolatedly, nevertheless at the percolation threshold, some long chains made up of CB aggregates ran through the rubber matrix, which resulted in the rapid increase in thermal conductivity value, and then with the addition of CB loadings, the number of chains increased. When the volume fraction was up to 26.2%, some three dimensional networks formed.

Moire Fringes on Precipitates in Quenched and Aged Beryllium

1968 ◽  
Vol 26 ◽  
pp. 426-427
Author(s):  
F. J. Fraikor ◽  
A. W. Brewer
Keyword(s):  
Ternary Phase ◽  
Volume Fraction ◽  
Age Hardening ◽  
Orientation Relationships ◽  
Solute Content ◽  
Moiré Fringes ◽  
Moire Patterns ◽  
Total Volume Fraction ◽  
Diffraction Patterns ◽  
Moiré Patterns

A number of investigators have examined moire patterns on precipitate particles in various age-hardening alloys. For example, Phillips has analyzed moire fringes at cobalt precipitates in copper and Von Heimendahl has reported on moire fringes in the system Al-Au. Recently, we have observed moire patterns on impurity precipitates in beryllium quenched in brine from 1000°C and aged at various temperatures in the range of 500-800°C. This heat treatment of beryllium rolled from vacuum cast ingots produces the precipitation of both an fee ternary phase, AlFeBe4, and an hcp binary phase, FeBe11. However, unlike a typical age-hardening alloy, the solute content of this material is low (less than 1000 ppm of Fe and 600 ppm of Al) and hence the total volume fraction of precipitates is small. Therefore there is some difficulty in distinguishing the precipitates and their orientation relationships with the beryllium matrix since the weak precipitate spots generally do not appear on the diffraction patterns.

Polymer composites as sensing materials for liquid organic solvents – preliminary results

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Stanislaw Frackowiak ◽  
Monika Maciejewska ◽  
Andrzej Szczurek ◽  
Marek Kozlowski
Keyword(s):  
Electrical Resistivity ◽  
Carbon Black ◽  
Polymer Composites ◽  
Percolation Theory ◽  
Liquid Mixtures ◽  
Organic Liquids ◽  
Volumetric Fraction ◽  
Factors Influencing ◽  
Benzene Toluene ◽  
Main Factors

AbstractCarbon black-filled polymer composites were investigated as sensing materials for organic liquids. Polypropylene and polystyrene which were selected as matrices and various amounts of carbon black were considered as the main factors influencing sensitivity of the composites in view of the percolation theory. Disposable filaments were produced of these materials. Change in their electrical resistivity was measured upon immersion in benzene, toluene, xylene, ethylbenzene and their mixtures. It has been found that studied materials were sensitive to the composition of liquid mixtures of organic solvent. Relationships between the filament response and volumetric fraction of the components were presented. The studied materials have shown promising sensing properties, which suggest their applicability for identification and quantification of multicomponent organic liquids.

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.

scholarly journals Effect of nano and micro conductive materials on conductive properties of carbon fiber reinforced concrete

2020 ◽  
Vol 9 (1) ◽  
pp. 445-454 ◽  
Author(s):  
Juhong Han ◽  
Dunbin Wang ◽  
Peng Zhang
Keyword(s):  
Carbon Fiber ◽  
Carbon Black ◽  
Steel Slag ◽  
Pressure Sensitivity ◽  
Electric Conduction ◽  
Conductive Materials ◽  
Slag Powder ◽  
Steel Slag Powder ◽  
Resistivity Variation ◽  
Nano Carbon

AbstractIn this study, the pressure sensitivity and temperature sensitivity of the diphasic electric conduction concrete were investigated by measuring the resistivity using the four-electrode method. The diphasic electric conduction concrete was obtained by mixing nano and micro conductive materials (carbon nanofibers, nano carbon black and steel slag powder) into the carbon fiber reinforced concrete (CFRC). The results indicated that, with the increase of conduction time, the resistivity of CFRC decreased slightly at the initial stage and then became steady, while the resistivity of CFRC containing nano carbon black had a sharp decrease at the dosage of 0.6%. With the increase of compression load, the coefficient of resistivity variation of CFRC containing nano carbon black and steel slag powder changed little. The coefficient of resistivity variation increased with the increase of steel slag powder in the dry environment, and CFRC had preferable pressure sensitivity when the mass fractions of carbon fiber and carbon nanofiber were 0.4% and 0.6%, respectively. Besides, in the humid environment, the coefficient of resistivity variation decreased with the increase of steel slag powder, and the diphasic electric conduction concrete containing 0.4% carbon fibers and 20% steel slag powder had the best pressure sensitivity under the damp environment. Moreover, in the dry environment, CFRC containing nano and micro conductive materials presented better temperature sensitivity in the heating stage than in the cooling stage no matter carbon nanofiber, nano carbon black or steel slag powder was used, especially for the CFRC containing steel slag powder.

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).

Research on Electrical Double Percolation of Carbon Black-Filled Cement-Based Composites

2011 ◽  
Vol 311-313 ◽  
pp. 201-204
Author(s):  
Hong Zhong Ru ◽  
Ran Ran Zhao
Keyword(s):  
Carbon Black ◽  
Cement Paste ◽  
Volume Fraction ◽  
Carbon Black Particle ◽  
Carbon Black Content ◽  
Percolation Behavior ◽  
Key Factor ◽  
Binder Ratio ◽  
Black Particle ◽  
Double Percolation

Electrical conductive carbon black-filled cement-based composites are significant as multifunctional structural materials. Double percolation in carbon black-filled cement-based composites involves both carbon black particle percolation and cement paste percolation, which has great effect on the resistivity of composites. Based on double percolation theory, the influences of sand-binder ratio and carbon black volume fraction on the resistivity of carbon black-filled cement-based composites are investigated. The results show that besides carbon black volume fraction, sand-binder ratio is a key factor affecting double percolation behavior in carbon black-filled cement-based composites. At a fixed carbon black content in overall mortar, with increasing sand-binder ratio, the cement paste percolation though aggregate phase increases due to high obstruction of aggregate but the carbon black particle percolation in cement paste decreases. This is because that the microstructure of aggregate is impenetrable so that the carbon black particles are limited in cement paste, that is, the carbon black content in paste is compacted and large amount of conductive paths are generated by lapped adjacent carbon black particles in paste. The double percolation in the electrical conduction in carbon black-filled cement-based composites is observed when the carbon black volume fraction is 7.5% and sand-binder ratio is 1.4, and its resistivity is only 3200 Ωcm, so that a sand-binder ratio of 1.4 and 7.5% carbon black volume fraction or more are recommended for attaining high conductivity with a compromise between workability and conductivity.

The Effects of Fiber Volume Fraction on the Experiment Modal Behavior of 45°/-45° Carbon Fiber Plain Woven Fabric/Epoxy Resin Composites

2012 ◽  
Vol 583 ◽  
pp. 150-153
Author(s):  
Qian Liu ◽  
Xiao Yuan Pei ◽  
Jia Lu Li
Keyword(s):  
Carbon Fiber ◽  
Epoxy Resin ◽  
Natural Frequency ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Laminated Composites ◽  
Woven Fabric ◽  
Resin Composites ◽  
Fiber Volume ◽  
Epoxy Resin Composites

The modal properties of carbon fiber woven fabric (with fiber orientation of 45°/-45°) / epoxy resin composites with different fiber volume fraction were studied by using single input and single output free vibration of cantilever beam hammering modal analysis method. The effect of different fiber volume fraction on the modal parameters of laminated composites was analyzed. The experimental results show that with the fiber volume fraction increasing, the natural frequency of laminated composites becomes larger and damping ratio becomes smaller. The fiber volume fraction smaller, the peak value of natural frequency becomes lower and the attenuating degree of acceleration amplitude becomes faster.

Determination of fiber volume fraction in a cured laminate

2021 ◽  
pp. 002199832110112
Author(s):  
Qing Yang Steve Wu ◽  
Nan Zhang ◽  
Weng Heng Liew ◽  
Vincent Lim ◽  
Xiping Ni ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Fiber Volume Fraction ◽  
Evaluation Method ◽  
Volume Fraction ◽  
Matrix Material ◽  
Volume Ratio ◽  
Gravimetric Analysis ◽  
Fiber Volume ◽  
Laser Ultrasonic ◽  
The Matrix

Propagation of ultrasonic wave in Carbon Fiber Reinforced Polymer (CFRP) is greatly influenced by the material’s matrix, resins and fiber volume ratio. Laser ultrasonic broadband spectral technique has been demonstrated for porosity and fiber volume ratio extraction on unidirection aligned CFRP laminates. Porosity in the matrix materials can be calculated by longitudinal wave attenuation and accurate fiber volume ratio can be derived by combined velocity through the high strength carbon fiber and the matrix material with further consideration of porosity effects. The results have been benchmarked by pulse-echo ultrasonic tests, gas pycnometer and thermal gravimetric analysis (TGA). The potentials and advantages of the laser ultrasonic technique as a non-destructive evaluation method for CFRP carbon fiber volume fraction evaluation were demonstrated.

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