Lee, S.-H.; Roh, J.-S. Changes in Functional Groups and Crystal Structure of Coal Tar Pitch with Respect to Carbonization Temperature. Crystals2024, 14, 122.
Lee, S.-H.; Roh, J.-S. Changes in Functional Groups and Crystal Structure of Coal Tar Pitch with Respect to Carbonization Temperature. Crystals 2024, 14, 122.
Lee, S.-H.; Roh, J.-S. Changes in Functional Groups and Crystal Structure of Coal Tar Pitch with Respect to Carbonization Temperature. Crystals2024, 14, 122.
Lee, S.-H.; Roh, J.-S. Changes in Functional Groups and Crystal Structure of Coal Tar Pitch with Respect to Carbonization Temperature. Crystals 2024, 14, 122.
Abstract
In this study, changes in the microstructure of coal tar pitch during successive processes, including pyrolysis, polycondensation, and crystallization, were examined in connection with the resulting variations in structure factors, as measured by XRD analysis, and functional groups, as confirmed by FTIR spectroscopy. To this end, four zones were defined based on variations in crystallinity, which were indicated by d002 and Lc. Each zone was further characterized by interpreting crystallinity development in relation to changes in functional groups and specimen height. At around 400 °C, polycondensation occurred as the C-Har and C-Hal peaks decreased in intensity. These peak reductions coincided with the formation of mesophase spheres, resulting in enhanced crystallinity. Subsequently, at around 500 °C, the peak intensity of C-H and COOH decreased, which was attributed to the release of large amounts of gasses. This led to sharp volume changes and a temporary reduction in crystallinity. All these results suggest that changes in the functional groups of coal tar pitch at lower temperatures (600 °C or less) during the carbonization process are closely associated with variations in its crystallinity. The major findings of the present study provide valuable insights for designing highly effective processes in the manufacturing of synthetic graphite blocks using CTP as a binder material, including by selecting appropriate temperature ranges to minimize volume expansion and crystallinity degradation and determining the lowest possible carbonization temperature to ensure adequate binder strength.
Keywords
coal tar pitch; carbonization; XRD; FT-IR; Functional group
Subject
Chemistry and Materials Science, Other
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
