Studies on Microstructural and Thermophysical properties of polymer nanocomposite based on polyphenylene oxide and Ferrimagnetic iron oxide

Nanocomposites of polyphenylene oxide (PPO) filled with nanoparticles of organically modified γ-Fe2O3, in varied concentration from 0 to 20 wt. %, were prepared. Thermal stability of these nanocomposites was evaluated by thermo-gravimetric analysis (TGA) and their dimensional stability was measured at sub-ambient as well as at elevated temperatures by thermo-mechanical analysis (TMA). The glass transition temperature (Tg) of the nanocomposites, measured by differential scanning calorimeter (DSC), was found to decrease with increasing weight fraction of γ-Fe2O3. Phase morphology of the nanocomposites was analyzed by scanning electron microscope (SEM). The distribution of γ-Fe2O3 in PPO matrix was studied by determining the iron using a X-ray energy dispersive spectroscope (EDX) attached to the SEM. These analyses reveal that the nanoparticles of γ-Fe2O3 with an average diameter of 20 nm were dispersed uniformly in the PPO matrix and also that there was very good matrix-filler adhesion. A detailed morphological study using a Gatan hot stage attachment with the SEM showed that there was no change in the surface morphology from ambient to high temperature up to 280 °C, beyond which segregation of the nanoparticles took place. Measurements by vibrational sample magnetometer (VSM) showed that the degree of saturation magnetization increased with increasing filler concentration from 0% to 10 wt. % of γ-Fe2O3. The magnetic nanocomposites, in general, also showed very good mechanical strength and high temperature resistance.