Surface morphology and chemistry of commercial carbon black and carbon black from vacuum pyrolysis of used tyres

The surface chemistry and morphology of carbon blacks obtained by pyrolysis of used tyres (CBp) and of commercial carbon blacks was investigated by electron spectroscopy for chemical analysis (ESCA), secondary ion mass spectrometry (SIMS) and fractal analysis using nitrogen adsorption data and small-angle X-ray scattering (SAXS). In contrast to commercial carbon blacks, carbonaceous deposits are formed on the CBp surface. The concentration of these carbonaceous deposits depends on the pyrolysis conditions, decreasing with decreasing pyrolysis pressure and increasing pyrolysis temperature. The carbon black surface is smoothed by the carbonaceous deposits. A relation exists between the fractal dimension, or roughness, of the CBp surface and the amount of carbonaceous deposits at constant pyrolysis temperature. The surface chemistry and morphology of CBp from pyrolysis at low pressures are similar to those of commercial rubber-grade carbon blacks. Copyright (C) 1996 Elsevier Science Ltd.