Influence of granular carbons on the pyrolysis behaviour of coal-tar pitches

The pyrolysis behaviour of pitches depends on their chemical composition which in turn depends on the processing conditions used in their preparation. When used as a precursor of carbon matrix composites, pitches are very often pre-treated (air-blowing, thermal treatment) to improve their properties and consequently those of the final material. The pyrolysis behaviour of treated pitches can be very different to that of the parent pitches, and it can also vary when mixed with different types of carbons for the preparation of composites. This work deals with the pyrolysis behaviour of four pitches of very different characteristics (a commercial impregnating pitch, an air-blown pitch and two pitches obtained by thermal treatment) when they are mixed with four granular carbons (anthracite, petroleum coke, foundry coke and graphite). The thermal analysis (TG/DTG and DSC) of pitches and pitch/carbon systems, optical microscopy and the toluene insoluble content of their pyrolysis products are used to monitor possible interactions between the two components during pyrolysis. (C) 2001 Elsevier Science B.V. All rights reserved.