Carbon black rubber

N. Nakajima and R. A. Miller, "Processing Ease and Rubber Carbon Black Interaction," paper presented atMCL meetings Montreal, 1987. 

FIGURE 35.11 Typical energy balance of one batch-mixing process on a GK320E mixer (styrene-butadiene rubber/carbon black [SBR/CB] compound). 

Results of a Fingerprint Analysis of a Masterbatch and Remill Mixing Process of a Styrene-Butadiene Rubber-Carbon Black (SBR-CB) Compound on a CK320E Intermeshing Mixer with PES3 Rotors (Harburg Freudenberger)... 

Standard method of test for accelerated ozone cracking of vulcanized rubber [Test method D-1149-64 (reapproved 1970)], pp. 554-560. In 1972 Annual Book of ASTM Standards. Part 28. Rubber Carbon Black Gaskets. Philadelphia American Society for Testing and Materials, 1972. 

Several of the major oil companies, such as Phillips Petroleum Co, have developed proplnts based on AN with synthetic rubbers carbon black. Some of these compns have been claimed to be capable of operation over the temp range -75°F to +170°F (Ref 7, p 11 Ref 8, p 114)... 

The amount of radicals in carbon black filled rubbers decreases significantly upon extraction of free rubber with the aid of a solvent containing a free radical scavenger. The extraction nevertheless causes a substantial increase in the fraction of the T2 relaxation component with the decay time of about 0.02-0.03 ms [62], This increase is apparently caused by an increase in the total rubber-carbon black interfacial area per volume unit of the rubber due to the removal of free rubber. The T2 relaxation component with a short decay time is also observed in poly(dimethyl siloxane) (PDMS) filled with fumed silicas [88], whose particles contain a minor amount of paramagnetic impurities. Apparently, free radicals hardly influence the interpretation of NMR data obtained for carbon-black rubbers in any drastic way [62, 79]. 

The subject of rubber-carbon black interactions was reviewed by the author (17) in 1965. At that time the principal conclusions could by stated roughly as follows ... 

The quantitative aspects of the flow of carbon filled polymer compositions are extremely complex. Not only do the primary structure aggregates possess a complex morphology, but secondary aggregation leads to thixotropic effects, while surface chemical interactions modify the medium. The flow of typical rubber-carbon black mixes is invariably non-Newtonian. 

Staining antioxidants such as AJ-isopropyl-AT-phenyl-/>-phenylenediamine [101-72-4] (36) are preferred for the manufacture of tires (see also Amines, AROMATIC, PHEN YLENEDI amines). These potent antioxidants also have antiozonant activity and retard stress cracking of the vulcanized rubber. Carbon black (qv), used in tires for reinforcement, hides the color developed by the antioxidant. According to use requirements, up to 3% of an amine antioxidant having antiozonant activity is added prior to vulcanization. 

Fillers in Rubber. Carbon black and calcium silicate are able to reinforce rubber. For example, the tensile strength of an SBR vulcanizate can be raised from 350 to 3500 Ib/in. by compounding with 50% of its weight of carbon black (54). The activity of the carbon black depends on particle size and shape, porosity, and number of active sites, which are less than 5% of the total surface. Elastomers of a polar nature, such as chloroprene or nitrile rubber, will interact more strongly with filler surfaces having dipoles, such as -OH and -CCX)H groups or chlorine atoms. 

Ingredients Natural rubber Carbon black N330 Zinc Oxide Processing oil Stearic acid phr 100 50 5 3 2 weight (g) 800 400 40 24 16 T2S0... 

Kaufman, S., SUchter, W. P., and Davis, D. O., Nuclear magnetic resonance study of rubber-carbon black interactions, J. Polym. Sci., A9, 829-839 (1971). 

Nishi, T., Effect of solvent and carbon black species on the rubber-carbon black interactions studied by pulsed NMR, J. Polym. ScL, B12, 685-693 (1974). 

There was little discussion of this perspective during the next 25 years, and only in the 1960s was there renewed attention. In 1962, Zakharenko et al. [Zl] in Moscow reported shear flow measurements of rubber-carbon black compounds. In 1972, Vinogradov et al. [V8], also in Moscow, reported similar results for other rubber-carbon black compounds and indicated the occurence of yield values. At the same time similar behavior was reported for talc-polypropylene compounds by Chapman and Lee [C8] of Shell and for titanium dioxide-polyethylene compounds by Minagawa and White [M29]. 

From about 1980, there have been extensive investigations of the shear viscosity of rubber-carbon black compounds and related filled polymer melts. Yield values in polystyrene-carbon black compounds in shear flow were found by Lobe and vhiite [L15] in 1979 and by Tanaka and White [Tl] in 1980 for polystyrene with calcium carbonate and titanium dioxide as well as carbon black. From 1982, White and coworkers found yield values in compounds containing butadiene-styrene copolymer [Ml, M37, S12, S18, T7, W29], polyiso-prene [M33, M37, S12, S18], polychloroprene [S18], and ethylene-propylene terpolymer [OlO, S18]. Typical shear viscosity-shear stress data for rubber-carbon black compounds are shown in Figs. 5(a) and (b). White et al. [S12, S18, W28] fit these data with both Eq. (56) and die expression... 

Recently, Osanaiye et al. [OlO] have made extensive measurements of creep in rubber-carbon black compounds at very low stresses. It was found that there were stresses below which there was no flow. The yield values determined by these authors were somewhat lower than those reported earlier. 

Studies of transient behavior of rubber-carbon black compounds were first reported by Mullins and Whorlow [M51, M52] in 1950. They found that there were strong time-dependent thixotropic effects in rubber-carbon black... 

Lobe and White [L15] studied stress relaxation following imposed strains in polystyrene-carbon black compounds and found that the stresses did not decay to zero, but to a finite value of stress roughly equal to the yield value of Eqs. (56) and (57). Montes et al. [M37] have found similar effects in rubber-carbon black compounds. This is shown in Fig. 7. Montes et al. found similar effects in stress relaxation following shear flow. 

There have been many studies of the dynamic viscosity ri o)) and complex viscosity of rubber-carbon black compounds and other filled systems. 

FIGURE 7 Stress relaxation in natural rubber-carbon black compound following flow, (a) NR 0 = 0.2. (b) NR 0 = 0.3. 

FIGURE 8 Comparison of rheological model of Eqs. (70)-(72) with experiment on rubber-carbon black compound, (a) Steady shear viscosity, (b) Transient, (c) Shear-rest-shear flow behavior. 

Middleman [M24], Goldstein [G8], Furuta et al. [Fll], Lobe and White [LI4], Toki and White [T7], Montes et al. [M37], Osanaiye et al. [OlO], and K. J. Kim and White [K8a]. The apparatus (with constant-temperature chamber) may be placed in a tensile tester and operated in a mode with a fixed velocity V giving a constant shear rate. It may, on the other hand, be used in a creep mode with hanging weights. This provides constant stress experiments. At low stress levels one needs to compensate for the weight of the central member which exerts a gravitational stress [OlO]. At very low stresses one may accurately determine the yield value of rubber-carbon black compounds. Osanaiye et al. [OlO] have made measurements at shear stresses below the yield value. 

Carbon black type Surface area Bound rubber, % Carbon-black loading, in phr ... 

Attraction between the polymeric phases and the fillers can occur through either physical or chemical interactions. Physical interactions have been extensively reported in rubber/ silica and rubber/carbon black composites [28,29] and usually involve physical adsorption... 

M. Gerspacher and C. P. O Farrel, Filler-filler and filler-polymer interactions as a function of in-rubber carbon black dispersion, in Proceedings International Rubber Conference 1997, Rubber Research Institute of Malaysia, Kuala Lumpur, pp. 184-193. 

A. A. Hon, J. J. C. Busfield and A. G. Thomas, Filler reinforcement in rubber carbon black systems, Constitutive Models for Rubber III, Lisse Balkema, 2003, 300. 

For hydrophobic elastomers such as NR and styrene butadiene rubber, carbon black usually has been selected as filler due to the hydrophobic surface characteristics and special particle shapes of carbon black which provide good dispersion. However, the dispersion of polar filler in hydro-phobic rubbers matrix is difficult because of its hydrophilic surface. The hydroxyl groups exist on the surface of polar filler provide strong filler-filler interactions which resulted in poor filler dispersion. The polar surface of filler formed hydrogen bonds with polar materials in a rubber compound. As known, the silica surface is acidic and forms strong hydrogen bonds with basic materials. ... 

A.M. Ismail, K.R. Mahmoud, M.H. Abd-El Salam, Electrical conductivity and positron annihilation characteristics of ternary silicone rubber/carbon black/TiB2 nanocomposites, Polymer Testing, ISSN 0142-9418 48 (December 2015) 37-43. http //dx.doi. org/10.1016/j.polymertesting.2015.09.006. 

PVC, LDPE, HIPS, ABS, EPDM, SBR, natural synthetic rubber, carbon black loaded PO... 

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