Interplay between curing kinetics and thermal aging dynamics of epoxy hybrid composites under different frequencies

Abstract This study presents the synergistic influence and mechanism of inorganic filler types on the thermal aging resistance of epoxy (EP) under different frequencies. Three different types of micro fillers, that is, aluminum nitride (AlN), aluminum oxide (Al ₂ O ₃ ), and boron nitride (BN) with a core‐shell nanofiller, that is, titanium dioxide coated with silicon dioxide (TiO ₂ @SiO ₂ ), are used to tailor the thermal and electrical insulation performance of EP. To investigate the long‐term stability of the prepared samples, all the samples are thermally aged at 130°C for 15 and 30 days. Various thermal, physicochemical, and electrical experiments are conducted before and after aging. The test results demonstrate that the neat EP suffers from a reduction in thermal and dielectric properties and exhibits significantly poor dielectric performance under high frequencies. However, EP hybrid composites exhibit less degradation of thermal and electrical performance even after 30 days of aging. It is anticipated that the curing dynamics, higher thermal conductivity of micro fillers, and dielectric barrier influence of TiO ₂ @SiO ₂ lead to superior thermal and electrical performance of EP hybrid composites when subjected to thermal aging. Highlights Epoxy co‐doped with BN@PDA/AlN@KH550/Al ₂ O ₃ @KH550 and TiO ₂ @SiO ₂ . Interplay between thermal conductivity and curing kinetics. Micro‐nano fillers enhances the thermal aging resistance of EP. Balanced content of micro‐nano fillers improves the electrical insulation properties. Finely tuned epoxy hybrid composites are excellent for long term applications even under high frequencies.