Influence of Coexistent Materials on the Formation of Carbonaceous Mesophase in Pitch (3)

Abstract

The effect of ferrocene in pitch on nucleation and growth processes of mesophase was investigated from the behavior of iron. The quinoline soluble coal-tar pitch to which ferrocene was added, was heat-treated at 430°C for a certain period. Quinoline insoluble part in the heat-treated pitch was separated by solvent extraction with quinoline. Then, the quinoline insoluble part was treated with HCl. Iron contents in the heat-treated pitch, the quinoline insoluble part, and the quinoline insoluble part treated with HCl were examined. The obtained results are as follows.Ferrocene added in pitch was already decomposed at 430°C and changed into the fine crystals of α-Fe and FeS, which covered the surface of mesophase spherules formed in pitch. The mesophase spherules were found to have almost the same size. Amounts of mesophase formation in the ferrocene-added pitch were larger than those in the pitch having no ferrocene content. From these results, it is considered that the iron crystals controll the size of mesophase spherules and accelerate the mesophase formation. Furthermore, when the mesophase coalesces each other, the crystals not only covers the surface of the coalesced mesophase but also exists inside the mesophase.It is also made clear that the shape of mesophase spherules changes from lemon-like form to spherical form with growth of mesophase spherules.