Carbonaceous mesophase of high solubility was prepared from A240 petroleum and coal tar (QI free) pitches by assuring homogeneous heating under a vigorous nitrogen flow and stirring. Anisotropie strings of the mesophase pitch were annealed above their softening temperature, causing coalescence and producing broad textures of flow domains. The fractions in the A240 mesophase pitch soluble in quinoline, pyridine or even THF showed anisotropy when recrystallized after fractionation. The solubilities of the various anisotropic fractions in the mesophase pitches produced from A240 and coal tar pitch are related to chemical structure. Molecular weight and the content of naphthenic and alkyl groups inherited from the starting structures appear to be the key factors controlling the anisotropy development and the solubility of the mesophase pitches.
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