Mesophase formation in defined mixtures of coal tar pitch fractions

A QI-free coal tar pitch is separated into a toluene-soluble (TS) and a toluene-insoluble (TI) fraction by solvent extraction. The effect of controlled mixing of both fractions on mesophase formation is studied. The formation of mesophase is correlated with the carbon and hydrogen contents of the sample materials. The influence of TI content on the viscosity and thus on the mesophase formation is measured in order to obtain viscosity data as a function of pitch composition for needle coke, carbon fiber, and carbon electrode manufacture.