2019 Volume 61 Issue 195 Pages 76-83
Carbon black consists of a number of carbon nanoparticles. To investigate the growth mechanism of carbon black, its morphology of nanoparticles with a comparable size is important. The particle size distributions of carbon black and nascent soot from ethylene or acetylene pyrolysis were analyzed by a scanning mobility particle sizer. Carbon black from pyrolysis was also classified by a differential mobility analyzer and collected by a thermophoretic sampling. The morphologies of size-graded carbon black were observed by scanning electron microscope in different experimental conditions. Particle size distribution showed that acetylene promoted soot formation more than that of ethylene at 1600–1800 K. From the results of image analysis, the morphologies of carbon black were complex with an increase in the mobility diameter of carbon black in long residence time because the number of particles increases with increasing mobility diameter. On the other hand, in short residence time, particle nuclei collided with aggregates, and the morphologies became simple. The temperature at which the ratio of complex morphologies was high depended on mobility diameter and/or residence time.
