Particle size distribution of carbon blacks by mercury porosimetry

Carbon blacks are made up of near-spherical elementary colloidal particles chained together in small clusters known as aggregates. These unique morpho logical characteristics have complicated their particle size characterizati on by conventional techniques. In this study the potential of mercury poros imetry for the generation of primary particle size distributions (PPSD) of carbon blacks is investigated. Two literature theories (Mayer-Stowe and Smi th-Stermer) were applied to derive PPSD curves from mercury porosimetry ana lyses of six ASTM standard reference blacks (series SRB A5-F5) covering a w ide range of particle sizes. Good agreement was found between particle size s expected from electron microscopy and those determined by mercury porosim etry. The advantages of the latter technique for the routine evaluation of continuous PPSD curves are discussed.