# Graphene and Iron Reinforced Polymer Composite Electromagnetic Shielding Applications: A Review
## 5 Polymer-Based Composites
### Graphene@Iron@Polymer Composites
#### 5.1.2 Interpretation of Graphene@Iron@Polymer Based Composites Articles
The concentration of TRG was from 0 to 5.5 vol% where the maximum total shielding effectiveness was achieved as 32 dB at 5.5 vol% while keeping the sample thickness as 2 mm [152]. [PERSON] et al. [153] synthesized thermally reduced graphene oxide (TRGO) and barium hexaferrite (BaFe) with thermoplastic TPU via the solution casting method. While keeping the sample thickness as 0.25 mm, EMI shielding effectiveness of -61 dB was achieved at 12.5 GHz frequency. Poly(3,4-ethylenedioxythiophene) (PEDOT) was synthesized with RGO and SrFe\({}_{12}\)O\({}_{19}\) nanoparticles through in-situ growth. The EMI shielding composite was tested in the X-band range where the shielding effectiveness of 42.29 dB was achieved with 2.5 mm thickness and 62 dB with 4.66 mm thickness [154]. PEDOT and RGO were also synthesized with PbTiO3 via chemical oxidative polymerization where the shielding effectiveness of 51.94 dB was achieved within the frequency range of 12.4-18 GHz at 2.5 mm thickness [155]. In another study PEDOT:PSS was synthesized with Fe\({}_{3}\)O\({}_{4}\) and RGO to form a shielding composite. The testing was made within the range of 2-18 GHz where the maximum reflection loss of \(-\)61.4 dB was achieved with 3.86 mm sample thickness [156]. [PERSON] [157] synthesized Fe\({}_{3}\)O\({}_{4}\) with carbon (C) and polypyrrole (PPy) via hydrothermal and chemical oxidative polymerization to form a shielding composite. It was observed that by keeping the carbon loading up to 2 wt.% and PPy up to 8 wt.%, with the sample thickness 0.8 mm, shielding effectiveness \(>\) 28 dB was achieved at 2-8 GHz frequency range. In another study, polypyrrole was used with FeCo and RGO to form a shielding composite via a three-step method. The testing was made within the range of 2-18 GHz where the maximum reflection loss of \(-\)40.7 dB was attained at 4.5 GHz when the sample thickness was 2.5 mm [158]. [PERSON] et al. [159] optimized three different polymer-based composites i.e., RGO-PANI-NiFe\({}_{2}\)O\({}_{4}\), RGO-PPy-NiFe\({}_{2}\)O\({}_{4}\) and RGO-PEDOT-NiFe\({}_{2}\)O\({}_{4}\). With a material thickness of 2.4 mm, 1.7 mm and 2 mm, a reflection loss of \(-\)49.7 dB, \(-\)44.8 dB and \(-\)45.4 dB was achieved within the 2-18 GHz frequency range. It can be observed that the highest reflection loss was achieved by the PANI polymer composite. [PERSON] et al. [160] synthesized polymethyl methacrylate (PMMA) with graphene and Li\({}_{0.35}\)Zn\({}_{0.3}\)Fe\({}_{2.35}\)O\({}_{4}\) where the testing was made within the range of 2-18 GHz. A reflection loss of \(-\)46.1 dB was achieved with 4 mm thickness. [PERSON] et al. [161] optimized PMMA and RGO to form a shielding composite where the testing was made within the X-band. With 2.9 mm sample thickness and 2.6 vol% RGO, shielding effectiveness of 63.2 dB was achieved. [PERSON] et al. [162] synthesized two different polymer composites for EMI shielding. The first combination was of PMMA with graphene, whereas, the second combination was of polyvinyl chloride (PVC). The shielding effectiveness of 21 dB and 31 dB was achieved within the X-band frequency range with sample thickness as 2 mm and graphene loading as 20 wt.%. [PERSON] et al. [163] synthesized Fe\({}_{3}\)O\({}_{4}\) with single-layer graphene-assembled porous carbon (SLGAPC) and polyvinyl alcohol (PVA) via the solution casting method. With a thickness of 0.3 mm, the shielding effectiveness of 20 dB was achieved in the X-band frequency range. [PERSON] et al. [164] used PVA, graphene (Gr) and magnetite (Fe\({}_{3}\)O\({}_{4}\)) to form a shielding composite. With 0.2 mm thickness and little graphene loading of 0.08 wt.%, shielding effectiveness of 40.7 dB was achieved within the X-band frequency range. [PERSON] et al. [165] explored polyether-ether-ketone (PEEK) polymer with GNP and carbonized lofah fibre (CLF) to form a shielding composite. Keeping the testing within X-band, shielding effectiveness of 27.1 dB was achieved with 9 wt.% of CLF. [PERSON] et al.