Abstract: The thermal decomposition of a series of polyanilines with different oxidation degrees and poly-o-toluidine was studied by Direct Pyrolysis Mass Spectrometry (DPMS) and Pyrolysis Gas Chromatograph/Mass Spectrometry(PGC/MS). The techniques of Collision Induced Decomposition (CID) and Tandem Mass Spectrometry have been used to investigate the mechanism of the chain cleavage.The results showed that the series of ions containing several units of polyaniline can be divided into two sources:benzene-diamine and guinone-deirnine units in polyaniline and its derivatines. The ratios of relative abandances of above ions were strongly influenced by the oxidation degrees. The mechanism of thermal decomposition of polyanilines and their derivatives was discussed.

Key words: direct pyrolysis mass spectrometry, polyaniline, oxidation degrees, thermal decomposition