On the ozone degradation of polypyrrole

Abstract

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 FeCl 3 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.