Physical Properties of Polymers Handbook · Carbon Black
This chapter presents the surface roughness, surface growth and surface energy distribution of carbon black (c.b.). The surface roughness of c.b. aggregates can be estimated by static gas adsorption techniques in the mono- and multilayer regime. For the morphological surface characterization in the monolayer regime, the variation of the estimated BET-surface area with the size of adsorbed probe molecules (yardstick method) is referred. Yardstick plot of graphitized black and FHH-plots of the nitrogen adsorption isotherms of two graphitized furnace blacks are illustrated. The chapter presents a hypothetical mechanism of c.b. formation that explains the universal value Ds ≈ 2.6 of c.b. surface topography on atomic length scales. The morphology of c.b. is closely related to the conditions of surface and primary aggregate growth during c.b. processing. Specific nitrogen surface area and DBP-number of the investigated c.b. samples are tabulated. Numerical and theoretical attempts are presented to explain c.b. formation which founded the statistical physics of surface growth mechanisms. The universal and scaling properties of the discussed growth models explain the universal topography of c.b. particle surface, independent of c.b. grade. The results concerning the energy distribution functions of ethene, calculated from the isotherms on a broad pressure range, lead to the conclusion that the examined furnace blacks have an energetic heterogeneous surface structure. With increasing particle size the amount of high energetic sites per gram of filler decreases dramatically showing the very different surface activities to polymers, respectively, the different reinforcement potentials of the fillers.