Novel nanocomposites of polypyrrole (PPy) dispersed with iron oxide (Fe2O3) particles have been synthesised by in situ chemical oxidative polymerisation of pyrrole in the presence of ammonium persulfate (APS) as an oxidising agent. The concentration of Fe2O3 was varied between 10-50wt% of PPy. The simultaneous polymerisation of pyrrole and oxide addition led to the complete synthesis of nanocomposites. A maximum dielectric constant of ∼28500 was observed at 20wt% of Fe2O3. The nanocomposites were characterised by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD analysis confirmed the structure and crystallinity of the nanocomposites, and a strong interaction between PPy and Fe2O3 particles was observed by FTIR technique. SEM and TEM images showed that Fe2O3 particles had been coated with PPy by establishing a network during the polymerisation process. The values of dielectric constant were obtained from capacitance measurements. The value of dielectric constant for nanocomposites with 20wt% of Fe2O3 was observed to be almost 12 times that of the pure PPy matrix. The high value of dielectric constant indicated a high packing density of Fe2O3 particles in PPy matrix. These nanocomposites have potential applications in electronic or biomedical devices.

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Nanocomposites of polyaniline with Fe 2 O 3 particles have been synthesized by chemical oxidative polymerization method by increasing the weight percentage of Fe 2 O 3 . The powder X ray diffraction tech nique was employed to study the structure and crystallinity of the synthesized nanocomposites. The strong interaction of polyaniline with Fe 2 O 3 particles was confirmed using FTIR technique. It was shown that poly aniline is dispersed into Fe 2 O 3 particles successfully by in situ polymerization and therefore the degree of crystallinity increased due to crystalline structure of Fe 2 O 3 particles. According to SEM and TEM data, most of Fe 2 O 3 particles were coated with polyaniline and those nanocomposites have formed a network during the polymerization process as well. Electrical conductivity of polyaniline containing 5 wt % of Fe 2 O 3 was higher among all other composites and even than PANI.