Mesophase development in petroleum and coal-tar pitches and their blends

Abstract

The behaviour of mixtures of an impregnating coal-tar pitch and a petroleum pitch during the early stages of carbonisation was studied, focusing on the formation and development of mesophase and the role played by primary quinoline insolubles (QIs). The blends were prepared in different proportions ranging from 20 to 80% of the impregnating pitch. The parent pitches and their blends were thermally treated at 430 °C for 3 h and the resultant products were characterized by thermal analysis and optical microscopy. The results showed that primary QIs not only control the coalescence of mesophase spheres but also the nucleation of new spheres in both parent pitches and their blends. Moreover, only the petroleum pitch was able to generate a massive amount of small spheres throughout the isotropic phase.