Restricted accessResearch articleFirst published online 2026-3
Mn-ZnO nanopowder to enhance the AC impedance,electrical conductivity,and physicochemical properties of epoxy transparent polymer insulating composites
This study explores the dielectric and AC impedance characteristics of epoxy transparent polymer insulating composites filled with Mn–ZnO nanopowder at various loadings. Measurements were conducted across frequencies from 3 kHz to 10 MHz to assess the impact of nanopowder concentration on charge transport and interfacial phenomena. The introduction of Mn–ZnO significantly enhanced AC conductivity due to interfacial polarization and space charge accumulation at filler–matrix boundaries, achieving a maximum value of 0.017 S/m at 10 MHz for the 0.2 wt% composite. This improvement highlights the material’s potential for electromagnetic interference (EMI) shielding applications. The bulk resistance (Rb) increased from 1.438 MΩ for pure epoxy to 1.976 MΩ at 5.0 wt% filler content, indicating strengthened potential barriers and enhanced charge scattering induced by Mn–ZnO doping. A progressive reduction in capacitor Q values with increasing filler content was observed, signifying decreased interfacial polarization and lower energy losses, advantageous for capacitor efficiency. Impedance spectra revealed frequency-dependent behavior, with higher resistance at low frequencies and reduced real impedance at high frequencies due to limited carrier motion. Fourier-transform infrared (FTIR) features confirmed successful filler incorporation. Overall, uniform dispersion of Mn–ZnO nanopowder is essential for achieving optimal dielectric and impedance performance in epoxy-based systems.
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