The Effect Of Nano-Al₂O₃ And Nano-TiO₂ And Their Fluorination On The Surface Insulation Properties Of Epoxy Resin

Epoxy resin(EP)nanocomposites have excellent thermal,mechanical and electrical properties and are widely used in the internal and external insulation of power systems.The doping of nano fillers can improve the tolerance of insulation,but so far there is no complete theory to explain the influence of that.So it is necessary to make further discussion,and to develop insulation materials with higher performanceIn this paper,nano-Al₂O₃ and nano-Ti O₂,were selected to modify epoxy matrix,and fluorination with low temperature atmospheric plasma method was used to pretreat the fillers,and prepare fluorinated composite materials.Measurements including canning electron microscope(SEM),back scattering electron spectroscopy(EDS),X-ray diffraction(XRD),Fourier infrared spectroscopy(FT-IR)and X-ray photoelectron spectroscopy(XPS)were used to characterize the fillers and composites before and after modification.The dielectric constant of the composite material was tested,and the influence of doping content,particle size and fluorination method of different fillers was analyzed.A simulation model of dielectric constant of two-phase composites was established by finite element method.The charge dissipation ability of the composites was tested,and the influence of various factors on the charge dissipation of the composite was analyzed.Based on the method of isothermal current decay(ISPD),the trap distribution of each composite sample was calculated,and the modification mechanism brought by fluorination and doping were reasonably explained from the microscopic perspective.The surface charge behavior of the Ti O₂/EP composites in DC field was simulated to explain the improvement of charge dissipation rate brought by the changes of dielectric constant and volume conductivity.Finally,the flashover voltage of composite materials before and after doping and fluorination modification was tested,and the influence of doping content,particle size and fluorination method of different fillers on flashover voltage was analyzed.