On the ozone degradation of polypyrrole

Polypyrrole, a conducting polymer, has been treated with ozone in a fixed bed reactor. Two different samples of polypyrrole (PPy) have been studied. PPy-Cl prepared by chemical oxidation of pyrrole with FeCl3 and PPy-Cl-DBSNa prepared using the same oxidant and an anionic surfactant sodium dodecylbenzenesulfonate (DBSNa). It has been shown by weight increase as function of time, by FT-IR spectroscopy of the samples, and by electronic spectroscopy that the sample PPy-Cl is one order of magnitude more stable toward ozone attack in comparison to the sample PPy-Cl-DBSNa containing the surfactant. The reactivity of polypyrrole with ozone is easily detectable by different techniques. The ozonized polypyrrole samples show a significantly worse thermal stability as measured by TGA-DTA in comparison with the pristine samples demonstrating the profound degradation caused by the exposure to O-3. PPy-Cl has been ozonized also in liquid phase in suspension or solution/suspension in different solvents. The electronic spectroscopy showed that the early stages of the ozonation reaction involve the interaction of ozone with the bipolaron and polaron defects of polypyrrole. (C) 2003 Elsevier Ltd. All rights reserved.