Influence of Graphene Nanoplatelet Lateral Size on the Electrical Conductivity and Electromagnetic Interference Shielding Performance of Polyester Nanocomposites

Abstract

Polyester nanocomposites reinforced with graphene nanoplatelets (GnPs) with two different lateral sizes are prepared by high shear mixing, followed by compression molding. The effects of the size and concentration of GnP, as well as of the processing method, on the electrical conductivity and electromagnetic interference (EMI) shielding behavior of these nanocomposites are experimentally investigated. The in-plane electrical conductivity of the nanocomposites with larger-size GnPs is approximately one order of magnitude higher than the cross-plane volume conductivity. According to the SEM images, the compression-induced alignments of GnPs is found to be responsible for this anisotropic behavior. The orientation of the small size GnPs in the composite is not influenced by the compression process as strongly, and consequently, the electrical conductivity of these nanocomposites exhibits only a slight anisotropy. The maximum EMI shielding effectiveness (SE) of 27 dB (reduction of 99.8% of the incident radiation) is achieved at 25 wt.% of the smaller-size GnP loading. Experimental results show that the EMI shielding mechanism of these composites has a strong dependency on the lateral dimension of GnPs. The non-aligned smaller-size GnPs are leveraged to obtain a relatively high absorption coefficient (≈40%). This absorption coefficient is superior to the existing single-filler bulk polymer composite with a similar thickness.

Recent advancements in the electromagnetic interference shielding performance of nanostructured materials and their nanocomposites: a review

“…Reduced graphene oxide has attracted considerable attention in the development of lightweight, multifunctional shielding materials. [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65] According to Yuan and coworkers, 46 a highly aligned laminated structure consisting of RGO foam showed EMI SE of $36-43 dB in the X-band. 46 Wu et al 47 studied the effect of annealing temperature on the permittivity and electromagnetic attenuation performance of reduced graphene oxide.…”

“…In view of this, an updated literature survey has been carried out below on the EMI shielding performance of carbon nanotubes, graphene and their inorganic material-based nanocomposites. 21–65…”

Recent Advances in Polymer Nanocomposites for Electromagnetic Interference Shielding: A Review

“…However, an increase in filler concentration can lead to poor dopant dispersion in the matrix and an increase in the viscosity of the medium. 78 A proper dispersion can be attained through surface adaptation and functionalization of fillers. Apart from the percolation threshold, the intrinsic conductivity of the filler also plays a key role in modifying the conductivity and EMI SE of the composite.…”

“…The main requirement is to achieve the percolation threshold with a minimum amount of fillers which can be made possible by proper dispersion of fillers. However, an increase in filler concentration can lead to poor dopant dispersion in the matrix and an increase in the viscosity of the medium . A proper dispersion can be attained through surface adaptation and functionalization of fillers.…”

Carbon Papers from Tall Goldenrod Cellulose Fibers and Carbon Nanotubes for Application as Electromagnetic Interference Shielding Materials

“…Carbon nanotubes (CNTs), which can be used as additives to improve the EMI shielding effectiveness, demonstrate an excellent electrical conductivity. Additionally, CNTs with a large aspect ratio show outstanding thermal and mechanical properties and are cost-effective compared to graphene [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Therefore, CNTs are considered to be promising EMI shielding additives.…”