Improved dielectric properties and highly efficient and broadened bandwidth electromagnetic attenuation of thickness-decreased carbon nanosheet/wax composites

Abstract

Carbon-based composites with various potential applications based on their unique properties are highly attractive. Lightweight electromagnetic attenuation composites embedded with carbon materials, specifically carbon nanosheets or graphene, are considered to offer promising attenuation performance due to their excellent electrical properties. Generally, graphene and carbon nanosheets are mostly achieved via chemical oxidation and subsequent reduction of commercial graphite, and the recovery of the electrical properties for the resulting products substantially depends on the reducing approaches. In this work, a direct chemical exfoliation approach has been applied to fabricate carbon nanosheets without sacrificing electrical properties. Thickness effects of the carbon nanosheets on the percolation threshold were investigated in the ethylene-vinyl acetate-based composites. These polymeric composites filled with thickness-decreased carbon nanosheets were found to exhibit much lower percolation threshold compared to those filled with unexfoliated ones. Thickness-dependent dielectric properties and electromagnetic attenuation were investigated via a direct comparison between unexfoliated and thickness-decreased carbon nanosheets along with corresponding paraffin wax-based composites. The enhanced complex permittivity and efficient electromagnetic attenuation coupled with broadened attenuation bandwidth were observed in the wax-based composites filled with thickness-decreased carbon nanosheets, and the related mechanism was discussed.