Efficient preparation of mesocarbon microbeads by pyrolysis of coal-tar pitch in the presence of rosin

Abstract

Mesocarbon microbeads (MCMB) were prepared by pyrolysis of coal-tar pitch in the presence of rosin, and characteristics of the pitch-rosin mixtures and the MCMB were studied. Pyrolysis behavior of the pitch-rosin mixtures was investigated by thermogravimetric analysis (TGA), and chemical structures of the pyrolysated pitch-rosin mixtures were studied using Fourier transform infrared spectroscopy (FTIR) technique. Optical textures of the pyrolysated pitch-rosin mixtures were characterized by polarized-light microscopy. In addition, morphologies and microstructures of the MCMB, extracted from the pyrolysated pitch-rosin mixtures, were studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Results show that the rosin addition contributes to a notable increase of MCMB yield as well as a decrease in the aromaticity index of the pyrolysated pitch-rosin mixtures. Moreover, the pyrolysis conditions have great effect on the morphologies and yields of MCMB. When the pitch-rosin mixtures are pyrolysated at 450 °C for 1.5–2.5 h, the MCMB yields arrive at 33.8–54.6 wt.% of the pyrolysated pitch-rosin mixtures.