Change in molecular assembly of mesophase pitch at higher temperature

Changes in molecular assembly of mesophase pitches at higher temperatures, especially at spinning temperatures were examined using a high temperature X-ray diffractometer, a fused ¹³C-NMR and an optical microscope with hot stage. Although anisotropic contents of all mesophase pitches used in the present study were 100 vol%, it was found that their assembly of constituent molecules even at room temperature was very different. Such a planar stacking changed markedly at higher temperature. Lc decreased with rising temperature at higher temperature than softening temperature, maintaining the ordered carbon content and the anisotropic content of 100 vol%.