THERMAL-STABILITY AND DEGRADATION OF SOME CHEMICALLY SYNTHESIZED POLYPYRROLE COMPLEXES

The thermal degradation processes in some chemically synthesized polypyrrole(PPY)/acceptor complexes and uncomplexed PPY of some specific intrinsic oxidation states have been studied by thermogravimetric (TG) analysis and X-ray photoelectron spectroscopy (XPS). In general, the PPY/acceptor complex, such as the PPY/perchlorate, PPY/halide and PPY/halobenzoquinone complexes, exhibit greater thermal stability over the deprotonated PPY (DP-PPY, consisting of 20-25% = N - structure) and the fully reduced PPY (PPY0, consisting of 100% - NH-structure). The temperatures for the onset of major weight loss in the PPY/organic acceptor complexes, such as the PPY/omicron-chloranil, PPY/p-chloranil and PPY/DDQ complexes, coincide approximately with the decomposition temperatures of the respective acceptors. All the PPY/acceptor complexes studied degrade initially via the loss or decomposition of the "dopants". The subsequent deprotonation process or the further loss of the dopant at high temperature is always accompanied by the appearance of the imine-like pyrrolylium nitrogens (= N - structure).