Abstract: Mesophase pitch is recognized as excellent precursor for making new carbon material. The quality of mesophase is closely related to the structural properties of its raw material. Distillate oils with different structural composition obtained from aromatic-rich oil were used for preparing mesophase pitch by thermal polycondensation. The molecular weight and molecular structure of the three distillate oils were characterized. The polarized optical microscopy, FT-IR, TG and XRD were used to analyze the optical texture, microcrystal and molecular structure of mesophase pitches for investigating the effects of molecular weight and structure of raw material on the formation and development of mesophase. The results showed that the structural composition of the raw material played an important role on the properties of mesophase pitch. It was found that the raw material with narrow molecular-weight distribution and more naphthenic structures was conducive to the generation of mesophase pitch with high content of anisotropic structure, low softening point and ordered crystal structure.

Key words: mesophase pitch, Aromatic-rich oils, vacuum distillation, polarization structure, microcrystal structure