Carbon black viscoelastic property

Thus, the APDS-modified carbon black provides viscoelastic properties comparable to TESPT-modified silica, which is now well known to be better in terms of hysteresis and hence roUing resistance compared to conventional carbon black. 

This customized function also circumvents the intractability problem pertinent to (19). Unlike the area function discussed previously to relate the physical properties of carbon black to the overall viscoelastic properties of the composite [229], the function introduced here is unique because it is a dimensionless quantity. Thus, it represents the property better and is devoid of any significant bias arising out of the differences in magnitudes of the constituting components. 

When a sinusoidal strain is imposed on a linear viscoelastic material, e.g., unfilled rubbers, a sinusoidal stress response will result and the dynamic mechanical properties depend only upon temperature and frequency, independent of the type of deformation (constant strain, constant stress, or constant energy). However, the situation changes in the case of filled rubbers. In the following, we mainly discuss carbon black filled rubbers because carbon black is the most widespread filler in rubber products, as for example, automotive tires and vibration mounts. The presence of carbon black filler introduces, in addition, a dependence of the dynamic mechanical properties upon dynamic strain amplitude. This is the reason why carbon black filled rubbers are considered as nonlinear viscoelastic materials. The term non-linear viscoelasticity will be discussed later in more detail. 

The effect of amplitude-dependence of the dynamic viscoelastic properties of carbon black filled rubbers has been known for some 50 years, but was brought into clear focus by the work of Payne in the 1960s [1-7]. Therefore, this effect is often referred as the Payne-effect. It has been also investigated intensively by... 

In parallel with this increase, certain undesirable properties which indicate viscoelastic behaviour become more marked as the proportion of carbon black is raised. These include stress-softening, compression set, hysteresis and heat build-up. Only comparatively insignificant increases become apparent, if at all, when nonreinforcing fillers are used. 

Wolff, S., Gorl, U., 1991. The influence of modified carbon blacks on viscoelastic compound properties. In International Rubber Confo-ence. 

Particle reinforcement in polymeric materials was first recognized for mbber compounds. This technique became possible when the relationship between stmcture and properties was understood for carbon black-filled namral rabber. The viscous component of the viscoelastic properties demonstrated that an enhancement in modulus was analogous to an increase in viscosity [29]. 

The resulting mixture has a quite complicated structure (Table 37-2). Normally, the amounts of additives are given in terms of parts per hundred parts of rubber, phr. The rubber provides the elastomer with the required viscoelastic properties. Sulfur forms the cross-link bridges between molecular chains the cross-linking shifts the property spectrum from viscous towards elastic. Carbon black as filler fulfills two functions to cheapen the product as a classical filler, and to increase the mechanical strength as what is known as... 

S. Wolff and U. Gorl, The Infiuence of Modified Carbon Blacks on Viscoelastic Compound Properties, Presented at International Rubber Conference, 1991. 

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. ... 

The effect of filler structure on the rubber properties of filled rubber has been explained by the occlusion of rubber by filler aggregates (45). When stmctin-ed carbon blacks are dispersed in rubber, the polymer portion filling the internal void of the carbon black aggregates, or the polymer portion located within the irregular contours of the aggregates, is imable to participate fully in the macrodeformation. The partial immobilization in the form of occluded rubber causes this portion of rubber to behave like the filler rather than like the polymer matrix. As a result of this phenomenon, the effective volume of the filler, with regard to the stress-strain behavior and viscoelastic properties of the filled rubber, is increased considerably. 

There are various types of carbon nanofillers which include carbon black, multi walled carbon nanotubes (MWCNTs), and single walled carbon nanotubes (SWCNTs) [27]. In this section the effect of these nano fillers on viscoelastic behavior is thoroughly discussed. The physicomechanical properties of conductive carbon black (CCB) filled ethylene acrylic elastomer (AEM) vulcanizates have been reported by B.P. Sahoo et al. They have discussed thoroughly about the effect carbon black concentration on the viscoelastic behavior of CCB-AEM nanocomposites with respect to temperature variation. Figure 10a, b represents the variation of storage modulus and loss modulus with temperature. It is observed that the value of storage modulus (E ) increased with increase in filler loading in the... 

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