Nanocomposite of polypyrrole-iron oxide by simultaneous gelation and polymerization

Simultaneous gelation and polymerization process has been used to prepare polypyrrole and iron oxide nanocomposites. The powder was annealed at different temperatures in the range 100-650 degreesC. These annealed composites were studied using X-ray, scanning electron microscope (SEM), transmission electron microscopy (TEM), thermo gravimetric and differential thermal analysis (TG-DTA) and Fourier transform infra red (FTIR). The size of the composites as determined from TEM was of the similar to10-30 nm in the temperature range 100450 degreesC. The X-ray studies revealed the presence of both the non magnetic alpha-Fe2O3 and the magnetic gamma-Fe2O3 and Fe3O4 phases. The electrical conductivity performed on the pressed pellets showed a maximum value for the sample annealed at 350 degreesC. The as prepared nanocomposites were found to be magnetic with the magnetization values decreasing with increasing annealing temperature. A transition from magnetic to nonmagnetic phase was observed, after the dissociation of polypyrrole. (C) 2002 Elsevier Science B.V. All rights reserved.