Electric Property Of Nano-SiO₂/EP Composites

Epoxy resins,with good acid and alkali resistance,corrosion resistance and excellent mechanical strength,are widely used as high voltage apparatus such as:bus,transformer bushing,wall bushings of insulating materials.Insulation partial discharge characteristics,breakdown strength,dielectric loss,thermal conductivity is an important indicator,directly determines the insulation applications.In order to make epoxy resins applied in high voltage,the more must improve the performance of epoxy resin insulation materials.Based on doped Nano-SiO2 particles in epoxy resin and look forward to using nano-SiO2 particles with Nano-effect to improve the electrical properties of epoxy resin,and study the impact of doping on the properties of nano-particles.First,use the coupling agent KH-550 Nano SiO2 particles as filler,quality of SiO2 nanoparticles prepared by melt blending,respectively Owt%,and 2wt%,and 3wt%,and 4wt%,and 5wT%,6wt%,7wt%,Nano-SiO2/epoxy resin(Epoxy Resin,EP)composite sample.Slicing microstructures using laser scanning microscope specimen,found dispersed Nano-SiO2 particles in epoxy resin matrix,can avoid the effect of Nano-particle agglomeration on the results.Then,set up a test platform,test composites of the partial discharge inception voltage,AC short breakdown strength,thermal conductivity,dielectric constant and dielectric loss rates,study of electrical properties of epoxy resin with Nano-doped SiO2 content increase trend.Experiment results showed that,composite of local discharge starting voltage with nano particles added volume of increased,rendering out first improve Hou declined of trend,in nano particles added volume for 5wT%Shi reached maximum value 33.5KV,more pure epoxy resin of 26.5KV improve has 22.5%;composite of Exchange short Shi breakdown strength with nano particles added volume increased of changes trend and local discharge starting voltage same,is first increased,Hou declined,in added volume for 5wT%Shi reached maximum value,By pure epoxy resin of 30.5KV improve to 36.5KV,improve has 15.87%;sample of media loss with nano particles added volume of increased,changes is unlikely to,but more not doping nano particles of epoxy resin are has declined,by pure epoxy resin of 1.25 ‰ maximum declined to 0.47 ‰;workers frequency dielectric constant by pure resin of 3.9 slightly has reduced,minimum value reached 3.65;thermal conductivity coefficient with Nano filler of increased and rendering first increased Hou declined of trend,5wt%Nano-SiO2 composite has the highest thermal conductivity of epoxy resin,is 1.57 times more pure epoxy resin.To sum up,added to the epoxy resin Nano-SiO2,can significantly improve the epoxy resin of the partial discharge inception voltage,AC short-time breakdown strength and thermal conductivity,and SiO2 nanoparticles doped to 5wt%maximum value of epoxy resin Nano-SiO2 particles doped with dielectric constant of dielectric loss and slightly lower,and with the changes of doped nano-particles,whose values have changed a little.