Study on the Carbonization Behavior of Petroleum-Based Mesophase Prepared by In-Process Hydrogenation

Abstract As an excellent precursor of high-modulus carbon materials, petroleum mesophase pitches' spinning performance was limited by its high softening point. Under the premise of ensuring the order degree of mesophase microcrystalline structure, the softening point was reduced by preparing mesophase pitch via in-process hydrogenation using fluid catalytic cracking aromatic-rich oil as raw material and decahydronaphthalene as a hydrogen supplier. The effects of in-process hydrogenation on the properties of mesophase and carbonization behavior during thermal polycondensation were investigated. It was found that the two-stage hydrotreated mesophase pitch produced an optical structure that was 100% generalized, with the highest crystal order of 0.9189, the highest aromaticity Iar of 0.520, and a softening point of 176 °C. The results showed that the addition of decahydronaphthalene promoted the hydrogen transfer reaction of the reaction system, producing light components such as cycloalkyl and saturates. The system mobility was improved, which made the molecular weight of the mesophase pitch concentrated and suitable for the full development of crystals.