A Study On Thermal Conductivity And Electrical Properties Of Epoxy Composites

Epoxy resin（EP）resin is widely used in the packaging of electronic devices and electrical equipment because of its excellent electrical insulation properties.However,the low thermal conductivity（TC）of EP limits its wider application and needs to be further improved.The current mainstream method for improving the thermal conductivity of polymer composite media is to construct a heat conduction path by filling high thermal conductivity inorganic fillers.Firstly,h-BN/EP and h-BN-T-ZnOw/EP composite media were synthesized by solution blending and hot pressing process,and the microstructure,phase structure,thermal conductivity,mechanical properties and insulation properties of the composite media were systematically characterized and analyzed.The results show that the composite filled h-BN-T-ZnOw/EP composite medium has good thermal conductivity and insulation.When the filling content of h-BN/T-ZnOw is 30 wt%/5 wt%,the thermal conductivity is 0.55 W/（m·K）at 25℃,which is 2.9 times higher than that of pure EP.At the same time,the volume resistivity of the composite medium is more than 10¹⁵ω·m,showing good insulation,but the breakdown strength of the composite medium decreases obviously.Compared with the simple blending,3D structures constructed by nanofillers with high thermal conductivity can greatly improve the thermal transfer performance of polymers.Then the EP matrix composite media with three-dimensional network structure was synthesized by ball milling,freeze drying and hot pressing,and the microstructure,phase structure,thermal conductivity and insulation properties of the composite media were systematically characterized and analyzed.The results show that the EP matrix composites filled with 3D hexagonic boron nitide/nanocellulosic oxide（h-BN/TOCNF）have good thermal conductivity and insulation.When the h-BN-TOCNF filling content is 9 wt%-21 wt%,the thermal conductivity is 0.86 W/（m·K）at 25℃.Compared with pure EP,the composite medium has 4.5 times higher resistivity than 10¹⁵ω·m and breakdown strength of 186.1 k V/mm,showing good insulation.This work provides an effective method to improve the thermoelectric properties of epoxy resins in electronic and electrical engineering applications.