POLYPYRROLE OVEROXIDATION DURING ITS CHEMICAL SYNTHESIS

The composition of the synthesis medium was investigated by high-perfo rmance liquid chromatography during the chemical polymerization of pyr role with FeCl3 in water. It is shown that the polypyrrole is simultan eously degraded during the synthesis in short soluble maleimide molecu les. This degradation process may be attributed to the polymer 'overox idation' which is described as a gradual polymer oxidation by water in the presence of FeCl3. Such a degradation is strongly enhanced at the beginning of the synthesis and leads to poor conductivity products. M oreover, such a degradation appears to be strongly amplified in low Fe Cl3 concentration solutions. Quantitative measurements confirm that po lymerization is second-order kinetics with respect to FeCl3 while over oxidation appears to be only first order. A consistent overoxidation m echanism is discussed.