Natural rubber carbon black reinforced

Obviously, there are many subtle differences in the structure, morphology, or network topology between radiation cured and sulfur cured elastomers, but their physical properties may be nearly equal, provided that precautions are taken to avoid the occurrence of chain scissions. A comparison of radiation cross-linked and sulfur cured natural rubber (gum and carbon-black-reinforced compounds) is in Table 5.4. ... 

Abstract Plasma polymerization is a technique for modifying the surface characteristics of fillers and curatives for rubber from essentially polar to nonpolar. Acetylene, thiophene, and pyrrole are employed to modify silica and carbon black reinforcing fillers. Silica is easy to modify because its surface contains siloxane and silanol species. On carbon black, only a limited amount of plasma deposition takes place, due to its nonreactive nature. Oxidized gas blacks, with larger oxygen functionality, and particularly carbon black left over from fullerene production, show substantial plasma deposition. Also, carbon/silica dual-phase fillers react well because the silica content is reactive. Elemental sulfur, the well-known vulcanization agent for rubbers, can also be modified reasonably well. 

Crystallization of oriented chains is, in various respects, important for the polymer properties. The fact has been mentioned before, that stereospecific rubbers such as cis-1,4 polybutadiene can crystallize when under strain. The spontaneously formed crystals contribute strongly to the strength of the vulcanizate. A vulcanized natural rubber has, without carbon black reinforcement, a tensile strength of about 40 MPa, whereas an unreinforced SBR breaks at about 3 MPa. (With SBR a high tensile strength can only be reached with carbon black.)... 

Figure 3.22 Stress-strain curves for natural rubber (a) without reinforcement and (b) with carbon black reinforcement, (e = X — 1) (From Ref. 25.)...

In the present paper, which is intended as a review of more recent progress only, emphasis is placed on the physical approach, but not to complete exclusion of the nature of the polymer-filler bond. Because of the overwhelming importance of carbon black as a reinforcing filler, and because most of the pertinent literature on reinforcement concerns carbon black filled rubbers, much of the discussion will be directed to carbon black reinforcement. However, the principles involved are general and apply qualitatively also to other fillers. 

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. 

Before the 1970s, carbon black reinforcement of elastomers was generally considered chemical by nature (Wiegand, 1925). It was supposed that carbon black surface acidic groups were reacting with natural rubber basic moieties conducting to a strong covalent bond that was responsible for carbon black reinforcement ability. 

APPLICATION EXAMPLES OF NANOMECHANICAL MAPPING 3.3.1 Carbon Black-Reinforced Natural Rubber... 

Nishi, T., Nukaga, H., Fujinami, S., and Nakajima, K., Nanomechanical mapping of carbon black reinforced natural rubber by atomic force microscopy, Chinese J. Polym. Sci., 25,35 1 (2007). 

Blends of two or more elastomers are used in a variety of rubber products to achieve different effects and end-use performance characteristics. The compatibility of elastomers in terms of their relative miscibility and response to different fillers and curing systems is of great importance to the rubber compoimder. From the standpoint of carbon black reinforcement, certain combinations of polymers can give less than optimum performance if the black is not proportioned properly between them. Note that equivalent volume proportionality of the black is not always desirable. This depends on the nature of the polymers and their relative filler requirements in terms of strength reinforcement. 

Automotive tires constitute the classic example of carbon-black reinforced elastomers. The elastomer can be either natural rubber—as typically is the case of truck and aircraft tires, or else a synthetic mbber—as is typical for automobile tires. However, reinforcing fillers constitute only one of many additives. There are also antioxidants, light stabilizers,... 

Carbon Black Reinforcement in Natural Rubber in Micro and Nano Length... 

Basically a polymer composite contains a polymer and a nonpolymer. While polymer composites include such compositions as foams and some types of gels, this chapter will be restricted to compositions of one or more polymers and one or more nonpolymers in the bulk state. There are a few points of overlap between blends and composites polymer-impregnated wood (where wood itself is a natural polymer blend), and organic fiber (e.g., polyester) reinforced plastics constitute examples. Compositions of special interest to this chapter include glass fiber reinforced plastics, carbon black reinforced rubber, and mineral-pigmented coatings. 

Crude petroleum is obviously vital to the rubber industry. All of the synthetic raw elastomers and the vast majority of the rubber compounding ingredients are directly dependent on petroleum as a feedstock. It is by far the most critical natural raw material for successful rubber production and fabrication. Without crude oil, at least in the short term, there would be no rubber industry as we know it today. There would be only natural rubber for the rubber base, no rubber accelerators, no effective antioxidants, no furnace carbon black reinforcement, and so on. In the long term, however, it would be possible to manufacture organic monomers and organic rubber chemicals from other carbon sources such as agricultural products and coal tar. However, this would result in major economic dislocations and require the development of a new infrastructure. 

Bokobza, L. and O. Rapoport, Silica and carbon black reinforcement of natural rubber. Macromolecular Symposia, 2003. 194 125-133. 

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