A study on the usage of nonwoven nanofibers in electrical insulating materials

Nonwoven nanofibers as a new material for possible improving properties of electrical insulation are considered in this paper. Polyamide nanofibers are used for modification of commonly used three-component mica-based high voltage electrical insulating material (epoxy resin, glass cloth and mica). Influence of different volume ratio and density of the nanofibers on the properties of resulting composites was analyzed. Melting behavior of nonwoven nanofibers and structure of resulting composites were examined by differential scanning calorimetry (DSC) and by scanning electron microscopy (SEM). Dielectric strength and voltage dependence of dissipation factor were subsequently tested. Mechanical properties were analyzed via Charpy impact test. The obtained results demonstrated that voltage dependence of dissipation factor showed interesting behavior especially at electric field intensity greater than 5kV/mm when the partial discharge activity starts to occur. Under these circumstances some of the modified composites are characterized by notable lower values of dissipation factor. Moreover, while the impact strength of some of the modified composite increased (of about 17%), dielectric strength stayed the same or better than expected.