Surface morphology of commercial carbon blacks and carbon blacks from pyrolysis of used tyres by small-angle X-ray scattering Original Research Article

The surface fractal dimension (Ds) of commercial rubber grade carbon blacks and pyrolytic carbon blacks (CBp) was determined using small angle X-ray scattering (SAXS). The CBp were produced by vacuum pyrolysis of used tyres at different temperatures and pressures. For the CBP a dependence of the pyrolysis conditions on the fractal dimension was observed. The fractal dimension decreases, suggesting a smoother surface, with increasing pyrolysis pressure and to a lesser intent with increasing pyrolysis temperature. Earlier SIMS and ESCA investigations have indicated that an evident correlation exists between the surface morphology and the surface chemistry of the CBp. According to these investigations, the smoothing of the CBp surface is due to the formation of carbonaceous deposits from adsorbed hydrocarbons on the CBp.