Significantly enhancing the thermal oxidative stability while remaining the excellent electrical insulating property of low density polyethylene by addition of antioxidant functionalized graphene oxide

This work reports the advance of utilizing antioxidant functionalized graphene oxide (GO) to enhance the thermal oxidative stability and retain the excellent electrical insulating properties of low density polyethylene. GO was first functionalized by a reactive antioxidant (AO) and then the AO functionalized GO (GO-AO) was coated with dopamine to avoid the adsorption of AO on the GO surface. The obtained products (i.e., polydopamine encapsulated GO-AO, RGO-AO) were used as filler to prepare low density polyethylene (LDPE) composites. The antioxidative efficiency of RGO-AO on LDPE was evaluated by oxidative induction time (OIT) of the composite samples. It was found that the addition of RGO-AO results in significantly prolonged OIT of the LDPE composites. For example, OIT of LDPE composite with 2.0 wt % RGO-AO increases to 19 min from 0.5 min of the pure LDPE. More importantly, the excellent electrical insulating properties of LDPE were retained in the RGO-AO/LDPE composites, which exhibit slightly enhanced dielectric constant, significantly suppressed dielectric loss tangent and decreased electrical conductivity when compared with the pure LDPE.