Investigation On The Preparation And Properties Of Epoxy-based High Voltage Insulating Dielectric

Electrical and electronic equipment is gradually developing towards lightweight,high frequency and integration,not only the insulating materials are required to have better electrical performance,but also higher requirements for thermal conductivity.Epoxy resin has excellent electrical properties,and is often used as a matrix material to prepare high thermal conductivity insulating composite materials,which are widely used in substrates and packaging of power equipment and components.On the basic of surveying of the relative literature about thermally conductive polymer composites,some composites are prepared,using Hexagon Boron Nitride as filler and epoxy resin as polymer matrix,and their properties are investigated.Low mass fractions of epoxy-nancron h-BN composite materials are prepared,and the effect of different mass fractions of h-BN composites on their thermal conductivity are investigated.The effect of h-BN nanosheets on the electrical properties of epoxy resins at different temperatures is rarely reported.In response to the problem,the effects of mass fraction,temperature and frequency on their electrical performances are discussed in detail.First,the experimental materials are selected,and the research plan is designed,and the h-BN/epoxy resin composites are prepared by blending and compounding.Then using some equipment to test the thermal conductivity and electrical properties of the composite materials,and studying the mechanism of influence.The results in the test range demonstrate that the thermal conductivity of composite materials is superior to that of neat epoxy.The thermal conductivity of composite materials increases with the mass fraction of h-BN,and their dielectric constant and dielectric loss increase with temperature.But the dielectric constant of composite materials decreases as the mass fraction of h-BN increases,and their dielectric losses first decreases and then increases as the mass fraction of h-BN increases.The volume resistivity of the composite materials first increases and then decreases as the mass fraction of h-BN increases,and the volume resistivity decreases with increasing temperature.Due to the change in the insulation properties and the internal heat accumulation of the composite material,the alternative current breakdown strength of composites first increases and then decreases as the mass fraction of h-BN increases.Additionally,the breakdown strength significantly degrades as the temperature increases.