Carbon black (CB) is a class of carbonaceous substance, composing of 96-99 wt.% carbon (C) and other atoms such as hydrogen (H), oxygen (O) and sulfur. The aggregates of CB are integrated with 4-6 primary particles and recognized to be indivisible units. In the commercial CB, the aggregates tend to form the agglomerates through Van der Waals forces. The fine structures of CB have long been a research topic with many debates. It is now well accepted that crystalline carbon (graphite) and amorphous carbon coexist in CB. The Sid Richardson model was proposed to elucidate the structure of CB. In this model [1], the outside of CB is mainly covered by graphitic carbon in the form of microcrystalline and the inner is mainly composed of amorphous carbon. Actually, fullerene, once laser-induced from graphite and reported by Kroto et al. in 1985 [2], was recognized to be one essential component of CB and its formation was a general phenomenon in hydrocarbon combustion [3]. Consequently, numerous investigations have been focused on fullerene structures in CB [4,5].
The agglomeration tendency and the surface activity of CB are two primary factors in determining its properties and consequential performance. The former can be determined by means of its structure and the latter can be estimated by its specific surface area. Besides the amorphous carbon and graphitic carbon, functional groups, including ketone, ether, ester, quinone, car-