Summary: | Abstract To study the effect of nano‐silica particles on the conductivity characteristics of ethylene propylene diene monomer (EPDM) insulation, EPDM nanocomposites with different mass fractions of nano silica were prepared via the melt‐blending method. Scanning electron microscopy was used to analyze the dispersion of nanoparticles in EPDM. Based on the Fourier‐transform infrared spectrum, the bonding properties between the nanoparticles and EPDM were analyzed. The steady‐state current at 30–100 °C and 1–20 kV/mm was measured. Moreover, the conductivity characteristic was analyzed. The experimental results show that as the content of nano‐silica increases, the electrical conductivity of EPDM nanocomposite as well as the threshold field strength gradually decreases. Samples with a small number of nanoparticles will increase the activation energy of the carrier conductivity, and the interface region effect introduced by nanoparticles will reduce the carrier mobility and concentration, resulting in a lower conductivity. Comparing the calculated value of the dielectric constant with the measured value can conclude that the high‐field conductance process is a combination of the electrode effect and the body effect, which in this case, Schottky effect dominates.
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