LAUSR

This paper focuses on the trap-modulated carrier transport in the alumina/epoxy nanocomposites (NCs) and its effect on the dielectric properties of NCs. The permittivity, conductivity, space charge and breakdown strength of the NCs are tested and the trap parameters are characterized. Results show that the effective permittivity and conductivity of NCs exhibit a lower value at filler loadings of 0.5 and 1 wt% compared with the neat epoxy, together with an enhancement in breakdown strength and a suppression in space charge accumulation. The improved dielectric properties at low filler loadings are attributed to the deep traps in the nanoparticle-polymer interfaces. The trap modulated carrier transport is formulated by Poole–Frenkel model, which demonstrates the introduction of deep traps could restrict the mobility of charge carriers, leading to the lower conductivity and enhanced breakdown strength.