A THERMOMECHANICAL TECHNIQUE FOR CHARACTERIZING PITCH

Thermomechanical analysis (TMA) in a tube-compressive mode can be used to characterize pitch in a reproducible and sensitive way. In a singl e experiment, this technique enables simultaneous determination of the glass transition temperature, the softening temperature and the rheol ogical behaviour of a pitch sample. Results on a typical Australian co al-tar pitch are consistent with Bingham fluid behaviour above its sof tening temperature with a yield stress of the order of 100 Pa. In a si milar test a petroleum pitch sample exhibited no yield stress.