Structure, thermal and dielectric studies of low-density polyethylene/cobalt ferrite hybrid nanocomposites

Abstract

This study elucidates the synthesis of CoFe₂O₄ nanoparticles via a sol–gel method using gelatin fuel and explores their incorporation into low-density polyethylene (LDPE) at varying weight percentages (0.0 wt % to 7.0 wt %). Systematic characterization was completed using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dielectric measurements. XRD patterns of CoFe₂O₄ nanoparticles exhibited diffraction peaks corresponding to the spinel structure. The average crystal size of CoFe₂O₄ in LDPE nanocomposites was 16–24 nm (Scherrer equation) and 15–55 nm (Williamson-Hall method). TEM analysis estimated the mean size of CoFe₂O₄ nanoparticles to be 17 nm. SEM images revealed nanoparticle-polymer interactions, particle distribution, and agglomeration at higher concentrations. TGA results indicated a marked increase in the decomposition temperature of LDPE composites. DSC analysis further demonstrates enhanced melting temperature (108–111 °C). The real part of the dielectric constant (ε₁) decreased up to 3 wt % of CoFe₂O₄ and then increased. The imaginary part of the dielectric permittivity (ε₂) increased with higher CoFe₂O₄ nanoparticle content. The resulting materials exhibit promising applications in electronics, energy storage, and electromagnetic shielding.