Transient Electromechanical Behavior of Carbon-Black-Filled Rubber

1987 ◽  
Vol 60 (4) ◽  
pp. 705-715 ◽  
Author(s):  
Donald R. Parris ◽  
Larry C. Burton ◽  
Muliawati G. Siswanto
Keyword(s):  
Dielectric Constant ◽  
Steady State ◽  
Carbon Black ◽  
Natural Rubber ◽  
Transient Response ◽  
Strong Correlation ◽  
Large Range ◽  
Qualitative Model ◽  
Electrical Measurements ◽  
Filled Rubber

Abstract This work has shown the sensitivity and uniqueness of conductivity and dielectric constant transient response to compressional stress for natural rubber filled with specific types of carbon black. The strong correlation between conductivity and capacitance (both steady-state magnitudes and transients) is attributed to the polymer itself. A qualitative model for these effects is based on changes of conductive and resistive microelements due to fracture of the carbon black matrix. Transient electrical measurements of this type should be applicable to carbon-black- (or metal-) filled dielectrics over a large range of resistivity.

Dependence of Thermal Conductivity of Carbon Black Filled Rubber on Several Factors

2009 ◽  
Vol 87-88 ◽  
pp. 536-541 ◽  
Author(s):  
Jun Ping Song ◽  
Lian Xiang Ma
Keyword(s):  
Thermal Conductivity ◽  
Carbon Black ◽  
Natural Rubber ◽  
Influencing Factors ◽  
Specific Area ◽  
Volume Percent ◽  
Filled Rubber ◽  
Two Factors

Five kinds of carbon black filled natural rubber were prepared, and thermal conductivity was studied considering two factors, which include temperature and volume percent of the filler. It was found that thermal conductivity had relevance to temperature and volume percent of carbon black, besides, structure and specific area of carbon black were also very important influencing factors. Moreover, reuniting phenomenon of nanometer grade of carbon black has much effect on thermal conductivity.

Effect of Crosslink Density on Cut Growth in Black-Filled Natural Rubber Vulcanizates

2002 ◽  
Vol 75 (5) ◽  
pp. 935-942 ◽  
Author(s):  
G. R. Hamed ◽  
N. Rattanasom
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Crack Growth ◽  
Crosslink Density ◽  
Longitudinal Crack ◽  
Test Pieces ◽  
Filled Rubber ◽  
Longitudinal Cracks ◽  
Natural Rubber Vulcanizates ◽  
High Crosslink Density

Abstract Tensile strengths, σb, of gum and N115-filled natural rubber test pieces, with and without edge pre-cuts, have been determined. At low crosslink density, the regular (uncut) σb of filled and gum vulcanizates is similar. However, at high crosslink density, the gum NR becomes brittle, while the corresponding filled rubber remains strong and resistant to cut growth. It is proposed that the tightly linked gum does not strain-crystallize appreciably during stretching, but that its filled counterpart does. Carbon black appears capable of inducing crystallization in a network that alone remains amorphous during extension. Filled vulcanizates of various crosslink densities have similar normal tensile strengths ( ≈ 30 MPa), but strengths differ, sometimes more than twofold, if a pre-cut is present. Lightly crosslinked specimens containing a small cut have strengths that depend very weakly on cut size, c. Furthermore, these develop long longitudinal cracks from which catastrophic rupture initiates. With larger cuts, strength decreases more rapidly with increasing c, there is less longitudinal crack growth, and rupture initiates near the original cut tip. In contrast, the strength of a highly crosslinked vulcanizate is sensitive to small cuts and test pieces exhibit minimal longitudinal cracking before failure.

Air Permeability of Elastomers by Diffusion Tests

1954 ◽  
Vol 27 (4) ◽  
pp. 996-1004 ◽  
Author(s):  
M. Czuha
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Large Range ◽  
Air Permeability ◽  
Solution Viscosity ◽  
Dilute Solution ◽  
Slight Effect ◽  
Structural Modifications ◽  
Styrene Copolymers ◽  
Mooney Viscosity

Abstract The permeability of various tread compounds to air was measured in a modified Warburg diffusion apparatus. Measurements were made at 30° C, with air applied at 48 psi. pressure, on molded disks approximately 0.025 inch thick and an area of 12.57 sq. in. The tests were reproducible within 4 per cent on control specimens. The compounds investigated showed permeabilities intermediate between the low values for Butyl and the high values for natural rubber. The permeability decreased with increasing combined styrene contents and with a decrease of temperature of polymerization for polybutadiene and low-styrene copolymers. It was unaffected by variation over a large range in polymer Mooney viscosity, gel content, and dilute-solution viscosity. A slight and almost linear decrease of permeability was found with increases in time of cure and carbon black loading for the stocks. In terms of the 300 per cent modulus, an increase of 100 psi. was accompanied by a 2 per cent decrease in permeability. Processing oil in the polymer had only a slight effect on permeability, when compared to the effects of compositional and structural modifications. Alfin and sodium, 75/25 BD/S, copolymers showed the lowest air permeability of the tread type of compounds that were studied.

COMPARISON OF STRESS–SOFTENINGS IN CARBON-BLACK FILLED NATURAL RUBBER AND STYRENE–BUTADIENE RUBBER

2013 ◽  
Vol 86 (4) ◽  
pp. 572-578 ◽  
Author(s):  
Julie Diani ◽  
Yannick Merckel ◽  
Mathias Brieu ◽  
Julien Caillard
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Cyclic Softening ◽  
Styrene Butadiene Rubber ◽  
Amplitude Dependence ◽  
Butadiene Rubber ◽  
Fatigue Lifetime ◽  
Filled Rubber ◽  
Filled Rubbers ◽  
Styrene Butadiene

ABSTRACT The authors compared the mechanical behavior and, more precisely, the Mullins and the cyclic (post-Mullins) softenings of two filled rubbers. A crystallizing natural rubber and a noncrystallizing styrene–butadiene rubber of similar compositions resulting in similar cross-link densities and filled with 40 phr of N347 carbon-black fillers were tested in cyclic uniaxial tension at room temperature and at 85 °C. Crystallization in filled rubbers is known to increase stress at high stretch, stretch at break, cycle hysteresis, and fatigue lifetime and to reduce crack propagation. In this study, it is shown that crystallization also seems to enhance the Mullins softening (softening at the first cycle) and to favor the apparent cyclic softening. Results reveal that natural rubber shows an amplitude dependence on the cyclic softening, whereas the styrene–butadiene rubber does not. Finally, results demonstrate that studying filled rubber softening cannot help predict lifetime.

Electrostriction of Natural Rubber Latex/Carbon Black Nanocomposites

2013 ◽  
Vol 844 ◽  
pp. 259-262 ◽  
Author(s):  
Darika Jaaoh ◽  
Chatchai Putson ◽  
Nantakan Muensit
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Carbon Black ◽  
Electric Field ◽  
Natural Rubber ◽  
Natural Rubber Latex ◽  
Low Frequency ◽  
Young Modulus ◽  
Filler Concentration ◽  
High Productivity

The purpose of this paper is to investigate an electrostrictive behavior of natural rubber (NR) and NR composites filled with carbon black (CB) nanopowders below percolation threshold. These NR elastomers present advantageous features such as a high productivity, elasticity, and ease of processing. In addition, such materials also exhibit the high induced strain and low young modulus for electrostrictive materials that can be used as actuators and energy harvesting. The NR and all composites were prepared by using solution casting method. The electrostrictive property of the composites was evaluated at low electric field (E 5 MV/m) by measuring the electric field induced strain Sz with the photonic displacement apparatus. The surface morphology of the samples was observed by the atomic force microscopy (AFM) and their electrical properties were analyzed as function of concentration and frequency in a range of 102105 Hz. The results show that the dielectric constant and the dielectric loss decrease when the frequency was increased. Moreover, the dielectric constant and the electrical conductivity strongly increase with increasing the CB contents, relate to interfacial charge distribution. While the dielectric loss slightly increases with increasing filler concentration. The electrostriction coefficient tended to increase with a higher CB loading. In comparison at CB 1 wt%, it was found that the electrostriction coefficient of NR composites is approximately 7 times larger than the pure NR. The NR nanocomposites thus seem to be very attractive for low frequency electromechanical applications.

Contribution of Carbon Black to Thermal Conductivity of Natural Rubber

2013 ◽  
Vol 561 ◽  
pp. 158-163 ◽  
Author(s):  
Jun Ping Song ◽  
Lian Xiang Ma
Keyword(s):  
Thermal Conductivity ◽  
Carbon Black ◽  
Natural Rubber ◽  
Filler Loading ◽  
Considerable Improvement ◽  
Middle Level ◽  
Rubber Composites ◽  
Filled Rubber ◽  
The Poor ◽  
Natural Rubber Composites

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.

Extraction and identification of fillers and pigments from pyrolyzed rubber and tire samples

1996 ◽  
Vol 54 ◽  
pp. 174-175
Author(s):  
P. Sadhukhan ◽  
J. B. Zimmerman
Keyword(s):  
Zinc Oxide ◽  
Electron Microscope ◽  
Carbon Black ◽  
Natural Rubber ◽  
Transmission Electron Microscope ◽  
Rolling Resistance ◽  
Synthetic Polymers ◽  
Nitrogen Atmosphere ◽  
Transmission Electron ◽  
Curing Agents

Rubber stocks, specially tires, are composed of natural rubber and synthetic polymers and also of several compounding ingredients, such as carbon black, silica, zinc oxide etc. These are generally mixed and vulcanized with additional curing agents, mainly organic in nature, to achieve certain “designing properties” including wear, traction, rolling resistance and handling of tires. Considerable importance is, therefore, attached both by the manufacturers and their competitors to be able to extract, identify and characterize various types of fillers and pigments. Several analytical procedures have been in use to extract, preferentially, these fillers and pigments and subsequently identify and characterize them under a transmission electron microscope.Rubber stocks and tire sections are subjected to heat under nitrogen atmosphere to 550°C for one hour and then cooled under nitrogen to remove polymers, leaving behind carbon black, silica and zinc oxide and 650°C to eliminate carbon blacks, leaving only silica and zinc oxide.

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