Preparation and Characterization of Electromagnetic Shielding Composites Based on Graphene-Nanosheets-Loaded Nonwoven Fabric

A fabric-like electromagnetic (EM) shielding composite based on nonwoven was fabricated using a coating method with a mixture containing graphene (GE) nanosheets and polyvinylidene fluoride (PVDF) adhesive agent, and then characterized for its mechanical properties, air permeability, EM properties, and morphologies. The GE loading amount and EM shielding effect was improved by applying a double coating process, with, in particular, a 2-sided coating that produced superior air permeability and shielding effectiveness (SE) than 2-layer coating. The coating produced an increased tensile initial modulus and flexural rigidity, whose increase was affected by the coating agent GE content. Increased GE content also resulted in decreased air permeability and increased SE and electrical conductivity. After coating with 25 g/L GE, the composite SE reached 31.2 dB, such that the electric/magnetic field strength of transmitted EM waves were reduced by ~97%. Scanning electron microscope and energy dispersive spectrometry results illustrated that aggregated GE was tightly bonded with the fibers due to the adhesive effect of PVDF and, with the increased coating agent GE content, the fibrous network was gradually filled with GE/PVDF attachments and increasing numbers of fibers were covered. Such an EM shielding material could be referenced for development by industrial or household protective applications.