Effect of Carbon Black on Dynamic Properties

How carbon blacks do affect the d5mamic properties in both the rubbery plateau and the transition zone is therefore a problem with tremendous technological implications, particularly when large amplitude strain are concerned (in practice when y 0.01 [i.e., 1%]). 

Region related with rolling resistance of a tire -J  

Dynamic properties of rubber materials with respect to tire technology requirements. 

As may be expected, dynamic properties are affected in a complex manner by CB type and level, frequency and temperature. No overall understanding is presently available, but a certain coherence emerges when reviewing the most significant effects of carbon blacks on dynamic properties, as reported in literature. 

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A. 1. Medalia, Effect of carbon black on dynamic properties of rubber vulcanizates. Rubber Chem. Technol. 51, 437 (1978). 

The principal effects of carbon black on the dynamic properties of elastomers were established as early as 1942. These can be summarized as an increase in both the elastic modulus and damping, compared with the unfilled material, and a pronounced strain-amplitude dependency, which is not found to a significant level in unfilled rubbers. It is true that any filler normally used in elastomers at least increases the elastic modulus, but the reason for the importance of carbon black is that no filler does it better. Not only does carbon black increase the modulus, it also improves the general strength and fatigue properties of elastomeric materials to a level which changes them from a curious hyperelastic novelty into a useful engineering material. 

The effects of the presence of carbon black on the dynamic mechanical properties of various types of filled rubber have been reviewed by Medalia [58]. In an early work (1939), Roelig [59] found that hysteresis increases with carbon black loading. Naunton and Waring [60] and later Gehman et al. [61] found that the elastic moduli of tread compounds decrease greatly with increases in strain. Stambaugh [62] attributed the reduction in modulus, with increases in strain, to the strain per se rather than to the increase in... 

Effect of carbon black level and temperature on dynamic properties. 

Effect of Carbon Black Dispersion on Dynamic Properties... 

Even dynamic measurements have been made on mixtures of carbon black with decane and liquid paraffin [22], carbon black suspensions in ethylene vinylacetate copolymers [23], or on clay/water systems [24,25]. The corresponding results show that the storage modulus decreases with dynamic amplitude in a manner similar to that of conventional rubber (e.g., NR/carbon blacks). This demonstrates the existence and properties of physical carbon black structures in the absence of rubber. Further, these results indicate that structure effects of the filler determine the Payne-effect primarily. The elastomer seems to act merely as a dispersing medium that influences the magnitude of agglomeration and distribution of filler, but does not have visible influence on the overall characteristics of three-dimensional filler networks or filler clusters, respectively. The elastomer matrix allows the filler structure to reform after breakdown with increasing strain amplitude. 

Unlike inert fillers that have little effect on physical properties, reinforcing fillers such as carbon black and Teflon add to the mechanical properties of the polymer [6], Both of the polymers for rotating dynamic seals examined here contain carbon black as a reinforcing filler. Teflon is added to polyetheretherketone to increase the lubricity properties of the polymer. Ninety percent of carbon black is obtained through furnace black, which involves the combustion of thermal cracking of hydrocarbons [7], This reaction takes place at 1,200-1,400°C ... 

The effect of the carbon black filler on the friction coefficient correlates with changes in the low temperature dynamic properties of the vulcanizate obtained using a torsion pendulum. The effect of contact pressure on the friction coefficient has been investigated using both filled and unfilled vulcanizates... 

COMPARISON EFFECTS OF PALM OIL FATTY ACID AND STEARIC ACID ON DYNAMIC PROPERTIES, CURING CHARACTERISTICS AND MECHANICAL PROPERTIES OF CARBON BLACK FILLED EPOXIDIZED NATURAL RUBBER COMPOUNDS Ismail H Kamal S K Mark S E Universiti Sains Malaysia... 

The effects of palm oil fatty acid and stearic acid on dynamic properties, curing characteristics and mechanical properties of carbon black-filled epoxidised NR compounds were studied. It was found that the scorch time and cure time increased with increasing... 

Nagata, N. Kobatake, T. Wantanabe, H. Uedia, A. Effect of chemical modification of solution-polymerized rubber on dynamic mechanical properties in carbon-black filled vulcanizates. Rubber Chem. Technol. 1987, 60, 837. 

Non-linear mechanical properties were observed for rubber eomposites and referred to as the Payne effect. The Payne effeet was interpreted as due to filler agglomeration where the filler clusters formed eontained adsorbed rubber. The occluded rubber molecules within filler elusters eould not eontribute to overall elastic properties. The composites behaved similarly to rubber composites with higher filler loading. Uniform and stable filler dispersion is required for rubber composites to exhibit linear viscoelastic behaviour. Payne performed dielectric measurements on SBR vulcanizates containing silica or carbon black. The dielectric data were used to construct time-temperature superposition master curves. The reference temperature increased with crosslinking but not significantly with filler. Comparison of dynamic mechanical and dielectric results for the SBR blended with NR was made and interpreted. ... 

I. Ulkem "Static and Dynamic Mechanical Properties of (Bauxide) and (Carbon Black) Filled SBR Vulcanizates Effects of Filler Surface Modification on Properties Ph.D. Thesis, Middle East Technical University, Dept, of Chem., Ankara, (July 1990), Paper is in Preparation. 

Osanaiye GJ (1996) Effects of temperature and strain amplitude on dynamic mechanical properties of EPDM gum and its carbon black compounds. J Appl Polym Sci 59 567-575... 

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