Effect of morphology and particle size of bismuth ferrite filler on the surface insulation of epoxy resin composites

Abstract The morphology and particle size of nanofillers have specific effects on their micro‐distribution parameters in the polymer matrix and macro‐properties of composites. In this study, bismuth ferrite nanoparticles (BFO) with different particle sizes were prepared by the sol‐gel route, and bismuth ferrite nanofibers (fBFO) were synthesized by electrospinning method, then were blended with epoxy resin as a filler to prepare the epoxy composites with multiple filler concentrations. The morphology and crystal structure of the filler were characterized by SEM and XRD. The effect of filler morphology and particle size on the surface insulation of composites was studied. We found that fBFO nanofibers have better dispersion in epoxy matrix, and fBFO/EP composites have more excellent surface insulation properties. Meanwhile, as the particle size of the filler increases, the flashover voltages of the BFO/EP composites increase. Finally, the simulation model of electric field inside EP composites were established and the trap distribution was calculated by isothermal surface potential decay method. The influence mechanism of filler morphology and particle size on the surface insulation properties of EP composites was further analyzed. BFO particles and nanofibers as fillers blended with epoxy resin have a great engineering application potential.