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 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.

Carbon Black Morphology in Rubber

1977 ◽  
Vol 50 (4) ◽  
pp. 842-862 ◽  
Author(s):  
G. C. McDonald ◽  
W. M. Hess
Keyword(s):  
Image Analysis ◽  
Carbon Black ◽  
Size Distribution ◽  
Surface Area ◽  
Surface Activity ◽  
Unit Size ◽  
Wear Rates ◽  
Rubber Compounds ◽  
Activity Structure ◽  
Black Surface

Abstract Electron microscope image analysis of carbon blacks in specific rubber compounds has greatly expanded the range of useful applications for studies of this type. This dispersed carbon-gel procedure has improved the sampling and test precision at operating speeds that are now reasonably comparable to the simple colloidal procedures for characterizing carbon black. Improved models have been developed for deriving black surface area and intraunit occlusion capacity. The EM image analysis approach has been useful in applying certain principles of reinforcement theory, as well as in explaining rubber property differences that are attributable to carbon black variables. Studies on hysteresis at constant strain (E″) have indicated that the important black variables, in diminishing order of significance, are loading, structure (intraunit occlusion and anisometry), unit size, unit size distribution, and surface activity. For hysteresis at constant energy (resilience), the most important black variables appear to be black loading, unit size, unit size distribution, surface activity, and structure. In terms of tread wear resistance (moderate wear rates with SBR-BR), a somewhat different pattern of carbon black variables is apparent. At constant loading, the most important black properties appear to be specific surface area, surface activity, structure, and unit size distribution. At any given tread wear-surface area level, hysteresis can be lowered by broadening the unit size distribution and increasing the surface activity of the black.

Predicting Useful Life of Green Tires through Different Methodologies

2019 ◽  
Vol 47 (2) ◽  
pp. 160-171
Author(s):  
Jordao Gheller
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Crack Growth ◽  
Critical Approach ◽  
Rubber Compounds ◽  
Different Temperatures ◽  
Useful Life ◽  
Tread Rubber ◽  
Complex Question ◽  
Reinforcing Filler

ABSTRACT One consideration when evaluating materials is the length of time over which they can be used, also called useful life. This is a complex question, especially for new green tire tread rubber compounds using silica as the main reinforcing filler that results in lower fuel consumption. The current work presents a critical approach of three methodologies used for predicting the useful life of different tire tread compositions. The methodologies considered were Arrhenius; Williams, Landel, and Ferry (WLF); and crack growth propagation. Different temperatures, strains, and mechanical properties were analyzed to evaluate the differences between the useful life of the new green tire tread and the carbon black reinforced reference one. Results showed different useful life for each evaluated property. Moreover, each tire tread composition presented a different useful life for the same property, while the silica reinforced composition presented a lower useful life when compared with the reference one.

Mechanisms of Rubber Abrasion in Unsteady State

1984 ◽  
Vol 57 (4) ◽  
pp. 755-768 ◽  
Author(s):  
S. W. Zhang
Keyword(s):  
Frictional Force ◽  
Sufficient Conditions ◽  
Unsteady State ◽  
Small Particles ◽  
Physical Processes ◽  
Rupture Length ◽  
Frictional Forces ◽  
Basic Characteristics ◽  
The Relationship ◽  
Quantitative Condition

Abstract Abrasion of rubber under the action of mechanical stress appears to involve two basic processes: micromolecular fracture and macrodelamination. The formation of ridges mainly results from the effect of tearing and tensile rupture, but the production of small particles is mainly due to the effect of microcutting. Ridge and small particle formation are basic characteristics of rubber abrasion. The physical processes during dry wear are gradual tearing leading to crack growth and also rupture of the tongue tip. A new concept of rupture length per revolution has been introduced, which is itself a function of the number of revolutions that have occurred during the unsteady state. Based on this, a quasi-theoretical relation for the rate of wear has been proposed. It reflects the influence of several factors on the rate of wear in a comprehensive way, and, it was verified by the experimental results. In the unsteady state of abrasion, the rate of wear and the spacing of the abrasion pattern not only depend upon the frictional force but also upon the number of revolutions. The relationship between the spacing and the frictional force is exponential. The influence of the rotational speed on the wear rate could be neglected when the speed did not exceed 18 rev/min. Oily wear was found at relatively small frictional forces (kN/F=0.24−0.41 m). The action of microcutting and the decomposition of the rubber are both prerequisites and sufficient conditions for oily wear to be produced. The same rubber shows two different modes of wear under different frictional forces. But a quantitative condition for the change from dry wear to oily wear is not yet clear.

Partial replacement of carbon black by nanoclay in butyl rubber compounds for tubeless tires

2017 ◽  
Vol 59 (11-12) ◽  
pp. 1054-1060 ◽  
Author(s):  
Mohan Kumar Harikrishna Kumar ◽  
Subramaniam Shankar ◽  
Rathanasamy Rajasekar ◽  
Pal Samir Kumar ◽  
Palaniappan Sathish Kumar
Keyword(s):  
Carbon Black ◽  
Butyl Rubber ◽  
Partial Replacement ◽  
Rubber Compounds

Approximate analysis of the containment of contaminated sites prior to remediation

2000 ◽  
Vol 42 (1-2) ◽  
pp. 319-324 ◽  
Author(s):  
H. Rubin ◽  
A. Rabideau
Keyword(s):  
Steady State ◽  
Peclet Number ◽  
Dimensionless Parameter ◽  
Contaminated Sites ◽  
Unsteady State ◽  
Péclet Number ◽  
Vertical Barrier ◽  
Time Period ◽  
Barrier Performance ◽  
Vertical Barriers

This study presents an approximate analytical model, which can be useful for the prediction and requirement of vertical barrier efficiencies. A previous study by the authors has indicated that a single dimensionless parameter determines the performance of a vertical barrier. This parameter is termed the barrier Peclet number. The evaluation of barrier performance concerns operation under steady state conditions, as well as estimates of unsteady state conditions and calculation of the time period requires arriving at steady state conditions. This study refers to high values of the barrier Peclet number. The modeling approach refers to the development of several types of boundary layers. Comparisons were made between simulation results of the present study and some analytical and numerical results. These comparisons indicate that the models developed in this study could be useful in the design and prediction of the performance of vertical barriers operating under conditions of high values of the barrier Peclet number.

scholarly journals Insights into the Payne Effect of Carbon Black Filled Styrene-butadiene Rubber Compounds

2020 ◽  
Vol 39 (1) ◽  
pp. 81-90
Author(s):  
An Zhao ◽  
Xuan-Yu Shi ◽  
Shi-Hao Sun ◽  
Hai-Mo Zhang ◽  
Min Zuo ◽  
...  
Keyword(s):  
Carbon Black ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Payne Effect ◽  
Rubber Compounds ◽  
Styrene Butadiene
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