Effect of carbon nanotubes addition on the carbonization behavior of coal-tar pitch

The influence of the addition of two carbon nanotubes (CNTs), namely, multiple-wall carbon nanotubes (MWNT) and OH-functionalized MWNT, on the carbonization behavior of coal-tar pitch was studied. The mixtures of coal-tar pitch and CNTs were prepared by ultrasonic-assisted dispersion in liquid phrase. The thermal behavior of the mixtures was studied by thermogravimetric analysis (TGA). In addition, the optical texture and micro-crystal structure of resultant cokes produced from carbonization of the mixtures were characterized by reflected polarized light microscopy and X-ray diffraction (XRD), respectively. The results show that the thermal stability of coal-tar pitch increases with the addition of CNTs, indicated by that the weight loss temperature and coke value is improved. Moreover, the addition of CNTs contributes to the formation of large anisotropic unit in some regions of the optical texture, which results in an increase in the heterogeneity of the micro-crystal structure of resultant cokes.