Nonlinear conductive performance and dielectric properties of MoS2 filled PEI matrix composite

Field grading composites showing nonlinear conductive performance are usually applied to protection for electrical systems. In this work, polyetherimide (PEI) matrix composite films with field-dependent nonlinear conductive behavior were fabricated by using a typical type of transition metal dichalcogenides, MoS 2 as filler. The MoS 2 filled PEI composite film showed a nonlinear coefficient of 6.92 at a relatively low filler content of 15 phr, which is the percolation threshold of this kind of composite film. Nonlinear conductive behavior of the MoS 2 /PEI composites was driven by tunneling effect. Conductivity of the 20 phr of MoS 2 filled composite film increased for almost 3 magnitudes within 20 kV/mm. Enhanced dielectric constant was brought to PEI by the MoS 2 fillers. The PEI containing 20 phr of MoS 2 showed a dielectric constant of 6.1 at 1 kHz with dielectric loss still being low. This work revealed the potential of MoS 2 being adopted as filler of field grading composites.