Preparation and Electrical/Thermal Properties of Epoxy/Polyacrylic Rubber‐Kaolinite Composites

Abstract Epoxy resin (EP) is widely used in electrical engineering for its excellent insulation and mechanical properties, with applications in transformers, motor insulation, and electronic encapsulation. To meet advanced demands, enhancing its thermal stability and insulation strength is crucial. In this paper, these properties were improved by introducing 4 wt% polyacrylic rubber dielectric elastomer (DE) and different contents of kaolinite micrometer flakes (KAO) into the EP matrix to prepare KAO/DE/EP composite films. The results show that the thermal decomposition temperature of the 4 wt% KAO/4 wt% DE/EP films was increased by up to 42.3 °C, and their AC breakdown strength reached 107.76 kV/mm, which is 33.4% higher than that of the pure EP (80.74 kV/mm), with the thermal stability and insulating properties greatly improved. At the same time, the relative dielectric constant of the composite film was further improved, and the AC conductivity and dielectric loss did not increase significantly. This experimental study provides a reference for researching the application of epoxy resin modification systems in the field of electrical engineering and integrated circuit packaging.