LAUSR

Abstract The present study aims at developing polyester/CoFe2O4 polymer nanocomposites, with enhanced thermal and electrical properties. The X-ray diffraction data of the samples revealed the semi-crystalline polyester nature and spinel crystal structure of CoFe2O4 nanoparticles. The average crystal size obtained from Scherer equation is 44 nm, which is smaller than that estimated from W–H method (59 nm). FTIR spectroscopy proved the complexation and interaction between polyester segments (–COOH and –OH) and CoFe2O4 nanoparticles via hydrogen ponding. DSC analysis showed changes in Tg values up to 116 °C and polyester/CoFe2O4 have revealed more thermal stability at temperatures Tonset, Tmax and T50 as seen from the TGA-DTG investigations. Dielectric real permittivity (e′) expressively increased by adding the CoFe2O4 nanoparticles, that is related to Maxwell-Wagner-Sillars (MWS) effect in hetero-phase composites. It has been found that CoFe2O4 nanoparticles enhanced the dissipation factor (tan(δ)) for all nanocomposites. The relative energy density (URelative) values are 4.39, 8.02, 10.7 and 11.3 for the polymer nanocomposites doped with 5.0, 10.0, 15.0 and 20.0 wt% of CoFe2O4 nanoparticles. Finally, the DC conductivity of nanocomposites increased with increasing the CoFe2O4 concentration.