SURFACE-MORPHOLOGY AND CHEMISTRY OF COMMERCIAL CARBON-BLACK AND CARBON-BLACK FROM VACUUM PYROLYSIS OF USED TIRES

The surface chemistry and morphology of carbon blacks obtained by pyro lysis of used tyres (CBp) and of commercial carbon blacks was investig ated by electron spectroscopy for chemical analysis (ESCA), secondary ion mass spectrometry (SIMS) and fractal analysis using nitrogen adsor ption data and small-angle X-ray scattering (SAXS). In contrast to com mercial carbon blacks, carbonaceous deposits are formed on the CBp sur face. The concentration of these carbonaceous deposits depends on the pyrolysis conditions, decreasing with decreasing pyrolysis pressure an d increasing pyrolysis temperature. The carbon black surface is smooth ed by the carbonaceous deposits. A relation exists between the fractal dimension, or roughness, of the CBp surface and the amount of carbona ceous deposits at constant pyrolysis temperature. The surface chemistr y and morphology of CBp from pyrolysis at low pressures are similar to those of commercial rubber-grade carbon blacks. Copyright (C) 1996 El sevier Science Ltd.