Structural Studies of dielectric HDPE+ZrO2 polymer nanocomposites: filler concentration dependences

Structural properties of HDPE+ZrO2 polymer nanocomposites thin films of 80-100 mu m thicknesses were investigated using SANS, XRD, Laser Raman and FTIR spectroscopy. The mass fraction of the filler was 1, 3, 10, and 20%. Results of XRD analysis showed that ZrO2 powder was crystallized both in monoclinic and in cubic phase under normal conditions. The percentages of monoclinic and cubic phase were found to be 99.8% and 0.2%, respectively. It was found that ZrO2 nanoparticles did not affect the main crystal and chemical structure of HDPE, but the degree of crystallinity of the polymer decreases with increasing concentration of zirconium oxide. SANS experiments showed that at ambient conditions ZrO2 nanoparticles mainly distributed like mono-particles in the polymer matrix at all concentrations of filler. The structure of HDPE+ZrO2 does not changes up to 132 degrees C at 1-3% of filler, excepting changing of the polymer structure at temperatures upper 82 degrees C. At high concentrations of filler 10-20% the aggregation of ZrO2 nanoparticles occurs, forming domains of 2.5 mu m. The results of Raman and FTIR spectroscopy did not show additional specific chemical bonds between the filler and the polymer matrix. New peaks formation was not observed. These results suggest that core-shell structure does not exist in the polymer nanocomposite system.