Effect of UV ageing on space charge characteristics of epoxy resin and its nanocomposites

This paper focuses on the space charge characteristics of epoxy resin and its nano-MgO composites exposed to UV irradiation. Compared with the pure epoxy resin samples, different space charge characteristics of the nanocomposites have been found. With the filler content increased (0.5 wt%~7 wt%), the total amount of charge first decreases, then increases, and then decreases again, then tend to be stable for samples experienced 200h UV ageing. Specimens with 3 wt%~5 wt% nano-MgO accumulate less space charge, while the 1 wt% nanocomposites accumulate the most. In addition, total charge of the composites with 3 wt%~5 wt% nanofiller appears almost stable after 50h UV ageing. Measurements of dielectric loss factor and volume resistivity also show that 3 wt%~5 wt% nano-MgO is benefit for the UV ageing resistance in epoxy-based materials.