carbonaceous mesophase
A liquid-crystalline state of @P04677@ which shows the optical birefringence of disc-like (discotic) nematic liquid crystals. It can be formed as an intermediate phase during @T06326@ (@P04961@) of an @I03353@ molten @P04677@ or by @P04795@ from @P04677@ fractions prepared by selective @E02301@. Generally, the spherical @M03849@ precipitated from a pyrolysing @P04677@ has the @B00747@. With continuous heat treatment the carbonaceous @M03849@ coalesces to a state of @B00754@ before @S05733@ to @G02697@ with further loss of hydrogen or low-molecular-@W06668@ compounds.
In the formation of carbonaceous @M03849@ by @T06326@ (@P04961@) of @I03353@ molten @P04677@, the development of a @LT06855@ is accompanied by simultaneous aromatic @P04740@ reactions. The reactivity of @P04677@ with increasing heat treatment temperature and its thermosetting nature are responsible for the lack of a true reversible thermotropic @P04537@ for the @B00754@ in most pitches. Due to its glass-like nature most of the liquid-crystalline characteristics are retained in the super-cooled solid state.
PAC, 1995, 67, 473. (Recommended terminology for the description of carbon as a solid (IUPAC Recommendations 1995)) on page 483 [Terms] [Paper]