![]() ![]() Typical properties of furnace blacks for inks, paints, paper and plastics. The properties of typical types of carbon black are presented in Tables 1– 6. Most commonly, the size distribution of airborne particles is expressed as its mass median aerodynamic diameter (MMAD) with its geometric standard deviation.Ĭarbon black is variously known as acetylene black, channel black, furnace black, lampblack or thermal black, depending on the specific process by which it is manufactured (see Section 1.2.1). The aerodynamic diameter can be measured by impactors and is dependent upon the geometric diameter, material density and shape factor of the aggregates. This is determined by the aerodynamic diameter of the particles. A standard method of measuring this property is by the dibutyl phthalate absorption of a black, in units of mL/100 g.Īlso of importance for human exposure is the behaviour of carbon black in air and its deposition in the respiratory tract upon inhalation. In addition to these two dimensions, there is a property or ‘structure’ which is the volume of space that is ‘reinforced’ by the aggregate - essentially, the amount of fluid it can absorb internally. This is called the aggregate size and is the dimension of the rigid framework that is the aggregate. To describe a carbon black aggregate, two dimensions are necessary:Įxtent of the branched chain aggregate. The aggregates can bind together by van der Waals forces in more loosely associated agglomerates, or they may be compressed in pellets (up to 0.5 cm) held together by means of binders (molasses/lignosulfonates) ( Dannenberg et al., 1992 Gardiner et al., 1992a). The chains are open structures and are used to absorb fluids and reinforce materials such as rubber. The aggregate may consist of a few or hundreds of spherical particles (or, as in thermal black, primarily single spheres rather than chains). This is a chain of roughly spherical carbon particles that are permanently fused together in a random branching structure. ![]() The fundamental unit of a carbon black is the aggregate. Structure is determined by the size and shape of the aggregated particles, the number of primary particles per aggregate and their average mass. A carbon black with a high degree of aggregation is said to have a high ‘structure’. Different types of carbon black have a wide range of particle sizes, high surface areas per unit mass, quite low contents of ash and toluene-extractable materials and varying degrees of particle aggregation. Carbon black is a powdered form of elemental carbon manufactured by the controlled vapour-phase pyrolysis of hydrocarbons. Carbon black is sometimes confused with soot but it is a very different material ( Medalia et al., 1981). ![]()
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