Carbon blacks properties

Carbon black can be described qualitatively by a series of properties particle size (and surface area) particle size distribution stmcture (particle aggregates) and surface activity (chemical functional groups such as carboxyl and ketones). 

TABLE 9.15 Nomenclature for Selected Elastomers (The Synthetic Rubber Manual, 1999) 

EPDM Terpolymer of ethylene, propylene, and a diene with a residual unsaturated portion in the chain EPM Ethylene-propylene copolymer 

HNBR Hydrogenated acrylonitrile-butadiene rubber (highly saturated nitrile 

Type ASTM Designation Particle Size (nm) General Use 

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The carbon black leaving the beading machine contains ca. 50 wt% water. It is dried in dryer drums, indirectly heated by burning tail gas. Dryer drums with a capacity of 2000 kg of carbon black per hour are 15-20 m long and 2-3 m in diameter. They are rotated at 5-15 rpm. Drying temperatures, generally between 150 and 250 °C, allow further modification of the carbon black properties. 

In the gas black process (Fig. 55), the feed stock is partially vaporized. The residual oil is continuously withdrawn. The oil vapor is transported to the production apparatus by a combustible carrier gas (e.g., hydrogen, coke oven gas, or methane). Air may be added to the oil-gas mixture for the manufacture of very small particle size carbon black. Although this process is not as flexible as the furnace black process, various types of gas black can be made by varying the relative amounts of carrier gas, oil, and air. The carbon black properties are also dependent on the type of burners used. 

These studies have dealt with materials suitable for fuel and feedstocks, the process for converting these materials to carbon black with predictable properties, the techniques for measuring and defining those properties, a better understanding of the effects of those carbon black properties on processing parameters of compounded goods, and the predictability of the performance properties of finished rubber goods. This presentation briefly considers the status of each of these areas of study relative to today s carbon blacks and tomorrow s rubber products. 

Bergemann K, Fanghanel F, Knackfuss B, Liithge T, Schukat G. (2004) Modification of carbon black properties by reaction with maleic acid derivatives. Carbon 42 2338-2340. 

One could also include the thermal black method in the group of thermal-oxidative processes, with the distinction that energy generation and decomposition reaction are not simultaneous. However, the fact that the actual carbon black formation takes place in the absence of oxygen and at decreasing temperatures results in carbon black properties that are markedly different from those achieved with thermal-oxidative processes. 

Research on carbon black continues and the most important topic remain its structure, the effect of functional groups on carbon black properties, the effect of the measured parameters of carbon black on its performance in various systems, and the influence of processing parameters on the product. These and other influences are discussed throughout the book. 

Irrespective of the shortcomings of laboratory abrasion tests, Eq. (36) qualitatively accounts for some important aspects of the dependence of roadwear on carbon black properties under severe conditions. The coefficient of friction is not particularly sensitive to carbon black addition... 

Foster, J.K. (1991) Effects of carbon black properties on conductive coatings. Presented at the 2nd International Exhibition of Paint Industry Suppliers, San Paulo, Brazil, On the Web at http // www.cabotcorp.com/cws/businesses.nsf/ 8969ddd26dc8427385256c2c004dad01/ 9d77475ac031436285256c7a005021dd/ FILE/CB-002.pdf. 

Achieving a good dispersion depends on selection of a carbon black grade that is as low as possible in surface area and as high as possible in structure. However, because the carbon black properties that produce the best dispersion frequently are not ideal for a given end use, it is necessary to determine a balance between dispersion qualities and end-use requirements. Other factors in a successful dispersion include the formulation and type of equipment to be used. 

In detail, the fast recovery is clearly related to the surface area and the structure of carbon black, the larger the surface areas by nitrogen absorption (see Chapter 9) and the lower the structure by dibutyl phthalate (DBF) absorption (see Chapter 9) the larger is the swell. The slow recovery was not clearly related to the carbon black properties. What causes the fast and slow recovery is the subject of future study. The fast recovery may primarily be related to the deformation of carbon black network and the slow recovery to the deformation of the rubber matrix. 

G. Kiihner. Reaction parameters and carbon black properties. Second Intermiional Conference on Carbon Black, MuUiouse, France, Sept. 27-30,1993. 

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