Quantitative determination of mesophase content in pitch

A quantitative microscopy method for measuring the mesophase content in pitch has been developed because conventional solubility methods often do not reflect mesophase contents accurately. The general technique utilizes area measurements on photomicrographs of polished specimens to determine volume percent mesophase. Slight modifications to the general method are necessary to overcome unique problems associated with measurements on low (0–15%), intermediate (15–70%) and high (70–100%) mesophase content pitches. Typical data are presented for samples from each regime. The limitations of the method are discussed.