Study On Low Temperature Performance Of Outdoor Epoxy Resin Composites

With the promotion of the Belt and Road Initiative,commonly used external insulation materials will be used in extreme environments with harsher environmental conditions,and the use temperature can be as low as-40? or lower,which raises higher aspects of material properties.Requirements.However,there are few researches on the low temperature performance of external insulating materials at home and abroad.It is not clear whether the materials can be used in extreme environments.Therefore,it is of great theoretical and practical significance to study the low temperature electrical and mechanical properties of typical outdoor electrical materials.In this paper,an outdoor alicyclic epoxy resin-based insulating material was used as the matrix,and different content of SiO2 filler was added to modify the water resistance,electrical properties and mechanical properties of the material at low temperature.A low temperature electrical and mechanical experimental platform for simulating extreme environments that can be used in experiments was built.The low temperature electrical test platform system includes power supply system,temperature monitoring and regulation control system,etc.The low temperature test chamber can provide a stable low temperature environment for the system,the lowest can be-70?,the error is 0.1?;the low temperature mechanics experimental platform is mainly from high and low temperature experiments.The box is combined with a universal testing machine and cooled with liquid nitrogen.On the basis of the established experimental platform,the hydrophobicity,DC flashover,DC breakdown,resistivity and tensile properties of the composites in the range of 20 ??-60 ? were tested,and the changes in temperature and filler content were analyzed.Observe the properties of the epoxy resin composite.Low temperature treatment will improve the water resistance and electrical properties of the material to a certain extent,as follows:as the temperature decreases,the contact angle of the epoxy resin composite material increases continuously,and the lower the treatment temperature,the longer the static contact angle changes.And finally stabilized near a fixed value;the DC flashover voltage at low temperature is higher than the flashover voltage value at 20? at normal temperature,the lower the test temperature,the higher the flashover voltage value;the DC breakdown field strength at low temperature The value is greater than the breakdown field strength at normal temperature,and the DC breakdown field strength reaches a maximum in the temperature range of-60?;as the temperature decreases,the volume resistivity of the epoxy composite increases.The effect of low temperature treatment on the mechanical properties of epoxy resin composites is mainly reflected in the decrease of tensile strength with temperature and the decrease of elongation at break.The addition of SiO2 filler can improve the electrical and mechanical properties of epoxy composite insulation to some extent:with the increase of filler content,the average value of static contact angle increases at the same temperature;the increase of SiO2 filler content makes DC flashover The electrical properties such as DC breakdown and resistivity are improved to varying degrees.At the same time,the introduction of SiO2 filler also improves the mechanical properties of epoxy resin composites.