OBTAINING MESOPHASE PITCHES FROM COAL TAR

Abstract

This article presents the results of research on mesophase pitch production from coal tar. The preparation of mesophase pitch was carried out by heat treatment in an argon atmosphere at temperatures of 300, 350, and 400 °C. The resulting carbon pitches were analyzed by scanning electron microscopy, Raman spectroscopy, and energy-dispersive analysis. An increase in the degree of surface degradation and the number of mesophase centers per unit area was observed with an increase in the treatment temperature to 300 °C. At 350 °C, a transition from an isotropic to an anisotropic structure was observed, where the mesophase centers were about 2 μm in size. A similar anisotropic structure was observed for a sample of coal tar obtained at 400 °C, and in some areas, a layered structure was observed, which could be associated with an increase in the graphitization degree of the samples. The particle size of the mesophase increases to 3.5-5 microns. The results of energy dispersive analysis showed that an increase in temperature leads to a decrease in the sulfur content. At 400 °C, sulfur is completely removed from the coal tar pitch composition. A correlation between the heat treatment temperature and the structure of the obtained pitch was established.