In-situ monitoring for mesophase formation processes of various pitches by means of high-temperature 13C-NMR

✍ Scribed by Kiyoshi Azami; Shunichi Yamamoto; Tetsuro Yokono; Yuzo Sanada

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 497 KB
• Volume: 29
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(91)90172-f

✦ Synopsis

High-temperature heating processes for coal-tar-derived pitch (pitch A), petroleum-derived pitch (pitch B), and hydrogenated petroleum-derived pitch (pitch C) have been studied by in-situ hightemperature '"C-NMR. Mesophase formation processes have been successfully monitored for all three kinds of pitches. The times required for appearance of mesophase in pitches A and B are similar and shorter than that in pitch C at 430°C. Time intervals from mesophase appearance to finishing mesophase transformation in pitches B and C are nearly the same and shorter than that in pitch A at 430°C. There may be a critical region of aliphatic carbon content for mesophase appearance of petroleum-derived pitch. Completion of mesophase development correlates to the line-width of characteristic peak of 180 ppm assigned as carbon in stacked aromatic layer molecules. Aliphatic carbons of molecules in mesophase seem to cause an increase of mesophase mobility and a narrowing of the characteristic peak for mesophase around 180 ppm.