SUITABILITY OF THERMOGRAVIMETRY AND DIFFERENTIAL THERMAL-ANALYSIS TECHNIQUES FOR CHARACTERIZATION OF PITCHES

The pyrolysis of a number of coal tar and petroleum pitches was studied by means of thermogravimetry, derivative thermogravimetry and differential thermal analysis (DTA). Acenapthylene was used as a model compound to interpret the results of pitch pyrolysis. DTA exo- and endothermal peaks were assigned to different types of phenomena such as devolatilization, polymerization, condensation and cracking. It was found that endothermal phenomena (devolatilization) are prevalent for binder coal tar pitches, whereas exothermal phenomena predominate for petroleum pitches. Results obtained with various pitch fractions provided evidence of interactions among constituents of fractions.