Properties of coal tar pitch-based mesophase separated by high-temperature centrifugation

Abstract

Mesophase pitches which have different mesophase contents were prepared from a coal tar pitch and separated into mesophase and isotropic phase by high-temperature centrifugation. Properties of mesophase during its nucleation, growth, and coalescence stages were investigated by measuring the solubility, density, C H atomic ratio, and thermogravimetric analysis. Mesophase pitch is easily separated into mesophase and isotropic phase by high-temperature centrifugation. However, when the mesophase content in pitch is above 82 vol%, the centrifugal separation becomes difficult because of a very small density difference between the mesophase and isotropic phase. The mesophase content in pitch was increased by centrifugal acceleration at constant temperature. The C H atomic ratio of the mesophase separated under higher centrifugal acceleration was also increased. QI was the main component of smaller mesophase spheres, and β-resin of the isotropic matrix contributed to the growth of spheres. The density and C H atomic ratio of mesophase were nearly constant at 1.385 g/cm 3 and 2.00, respectively, during heat treatment.