THERMOCHEMICAL AND STRUCTURAL CHANGES IN COAL-TAR PITCH DURING CARBONIZATION.

Physicochemical and physical procedures have been used for several years in the investigation of pitches, but the chemistry of the thermal degradation of pitch and its components is still known in only very broad outline. This investigation was made to study the relationships between the thermochemical changes that take place in pitch and the structural changes in its intermediate solid products (carbonizates). Tests carried out on samples of coal-tar pitch after heating to different temperatures show that under the given heating conditions (heating rate 3 K/min, soaking period 1 h at the final temperature, inert medium), the optimum temperature for the thermal polymerization of pitch is 400 degree C.