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

2010 ◽  
Vol 146-147 ◽  
pp. 575-580
Author(s):  
Jun Ping Song

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.

2011 ◽  
Vol 221 ◽  
pp. 466-471 ◽  
Author(s):  
Jun Ping Song ◽  
Yan He ◽  
Lian Xiang Ma

Graphitized carbon black 40b2 and acetylene black were filled separately in natural rubber matrix for preparing vulcanized rubber. The thermal conductivity of both kinds of composites was studied considering filler loading and temperature. SEM and TEM were applied to observe morphology of the filler and composites. The experimental results show that thermal conductivity of acetylene black/rubber composites is much better than that of graphitized carbon black 40b2/rubber composites, which is opposite to the electric conduction properties. As filler loading increased, the difference increased, and when the filler loading is up to 40phr, the thermal conductivity value of acetylene black/rubber composite is 53% larger than the other one. TEM shows that acetylene black has more botryoidal structure, larger carbon black aggregates in size, and much looser surface than 40b2.Moreover, for acetylene black, particles contact by surface mainly, and for 40b2, particles contact by point mainly. SEM shows that the distribution of carbon black 40b2 in rubber matrix is much better than acetylene black. The better thermal conductivity for acetylene black is attributed to the higher structure, nonuniform distribution in rubber matrix and surface contact between particles.


2011 ◽  
Vol 137 ◽  
pp. 1-6
Author(s):  
Qing Li ◽  
Xiao Xiang Yang

In this paper, the micromechanical finite element method based on Representative Volume Element has been applied to study and analyze the macro mechanical properties of the carbon black filled rubber composites by using two-dimensional plane stress simulations and three-dimensional axisymmetric simulations under uniaxial compression respectively. The dependence of the macroscopic stress-strain behavior and the effective elastic modulus of the composites, on particle shape, particle area/volume fraction and particle stiffness has been investigated and discussed. Additionally, the simulation results of the two-dimensional plane stress model and the three-dimensional axisymmetric model are evaluated and compared with the experimental data, which shows that the two-dimensional plane stress simulations generate poor predictions on the mechanical behavior of the carbon black particle reinforced rubber composites, while the three-dimensional axisymmetric simulations appear to give a better prediction.


2011 ◽  
Vol 221 ◽  
pp. 373-376 ◽  
Author(s):  
Ze Peng Wang ◽  
Yan He

Thermal conductivity of rubber composites filled with CNTs (carbon nanotubes) and N234 CB (carbon black) were investigated. Result indicated that Thermal conductivity of NR (natural rubber) filled with CNTs is higher than that of NR filled with CB in the case of the same filling amount. CNTs can better improve the performance of thermal conduct of rubber composites than CB. The more the filling content of CNTs is, the higher thermal conductivity of NR composites.


2013 ◽  
Vol 844 ◽  
pp. 255-258 ◽  
Author(s):  
Suradet Matchawet ◽  
Charoen Nakason ◽  
Azizon Kaesaman

Electrical and mechanical properties of epoxidized natural rubber (ENR-25) filled with conductive carbon black (CCB) have been investigated. SEM was used to analyze dispersion of CCB particles in rubber matrix. The results indicated that the AC conductivity increase with increasing volume fraction of carbon black as well as frequency. The percolation thresholds of the electrical conductivity was found at 0.10 volume fraction of CCB. Furthermore, addition of CCB at volume fraction 0.05 caused the highest tensile strength of the composites. The tensile strength and elongation at break were decreased with increasing content of CCB greater than 0.05 volume fraction. However, the volume fraction of CCB at 0.10 demonstrated the most suitable proportion for the ENR composites with superior electrical and mechanical properties.


2013 ◽  
Vol 561 ◽  
pp. 158-163 ◽  
Author(s):  
Jun Ping Song ◽  
Lian Xiang Ma

Eight kinds of carbon black filled natural rubber composites were prepared, and thermal conductivity was studied. Acetylene black contributes much to the thermal conductivity of rubber, and tiny loading results in considerable improvement. The conductive carbon black 40B2 is advantageous for the improvement in thermal conductivity of rubber when its loading reaches middle level, and at its middle level, also tiny loading results in much improvement. Most kinds of carbon black for rubber application filled rubber composites have good properties except for N134 and N660, especially the poor contribution of N660. Additionally, in the case of carbon black filled rubber composites, addition of filler may not necessarily benefit the thermal conductivity when filler loading is not much.


RSC Advances ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 636-644 ◽  
Author(s):  
J. M. A. R. B. Jayasinghe ◽  
R. T. De Silva ◽  
Rohini M. de Silva ◽  
K. M. Nalin de Silva ◽  
M. M. M. G. P. G. Mantilaka ◽  
...  

Thermal conductivity of natural rubber was enhanced by incorporating novel conductive hybrid nanofillers, namely polyaniline grafted carbon black nanoparticles and carbon black nanoparticles linked with carbon microfiber composites.


2011 ◽  
Vol 311-313 ◽  
pp. 201-204
Author(s):  
Hong Zhong Ru ◽  
Ran Ran Zhao

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.


2013 ◽  
Vol 753-755 ◽  
pp. 2379-2382
Author(s):  
Shi Meng Xu ◽  
Run Bo Ma ◽  
Jian Hua Du ◽  
Jun Hong Liu ◽  
Qi Jin

Filled the N330 carbon black, silica T80 carbon black and Al powder and Fe2O3 magnetic nanoparticles, the rubber composites on multi-component electromagnetic fillers were prepared according to orthogonal experiment analysis, and the preliminary experiment conclusions of the filler prescription designs were given; Based on the experiment design, the mechanical properties and thermal conductivity of the rubber composite were tested, and the testing results were analyzed by using variance analysis. Thus, the paper shows that the effects of N330 on rubber mechanical properties are significant, and the effects of Al powder on the rubber thermal conductivity are significant. Moreover, it is highly emphasized in this paper that the orthogonal experiment design must be carefully explored before the tests are executed.


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