The evaluation of the effect of metal oxide and ferroelectric ceramic additives on the structural and dielectric properties of epoxy matrix

This study focused on examining and comparing the effects of Bi2O3, WO3, and ferroelectric Bi2WO6 ceramic particles on the frequency-dependent electrical properties of an epoxy matrix, which is known for its good mechanical strength, easy processability, high oxidation resistance, low dielectric loss, and sealing and adhesive properties. The reinforcing particles as well as the composites were examined by Fourier transform infrared analysis, and electrical measurements were carried out at room temperature with an impedance analyzer in the range 20 Hz to 1 MHz. The energy storage performances of the three composite families were compared by limiting the analysis to the real and imaginary components of the complex dielectric constant (epsilon' and epsilon"), the AC conductivity, and the phase angle. When the epsilon' and epsilon'' values of the pure epoxy and the 20% by mass Bi2O3, WO3 and Bi2WO6 doped composites were compared it was observed that WO3 additive causes higher epsilon' values than the other additives in the entire frequency region, ignoring the high dielectric loss. However, when epsilon' and epsilon'' were evaluated together, Bi2O3 and Bi2WO6 additives caused lower dielectric loss than WO3 and higher epsilon' values than pure epoxy which make these additives more advantageous than WO3 for energy storage applications. In addition to these examinations, frequency-dependent phase angle evaluation has suggested that 30% Bi2O3 and 20% Bi2WO6 additives can be considered promising for energy storage applications in the high-frequency region. (c) 2023 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry.