Characterisation of coal tar pitches by thermal analysis, infrared spectroscopy and solvent fractionation

Four commercially available coal tar pitches have been characterised throug h the combination of conventional techniques used for pitch characterisatio n, like elemental analysis and solvent fractionation, and infrared spectros copy (FTLR) and thermal analysis (thermogravimetry (TG)-differential therma l analysis (DTA)). The results obtained from this set of experiments provid e suitable information to establish differences between the materials accor ding to their industrial origin and preparation method. The differences fou nd are a consequence of the distinct chemical composition of the pitches (d etermined by FTIR), as well as the dissimilar chemical interaction that exi sts between the molecules of different fractions of the parent pitch (evide nced from DTA). These observations are responsible of the clear differences found between a given pitch and its respective insolubles, and affect thei r applications, i.e. in the area of carbon fibre preparation. (C) 2000 Else vier Science Ltd. All rights reserved.