# 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  
Different fillers are used with polymer composites to enhance the underlying matrix material. Carbonaceous fillers such as carbon black, carbon nanotubes, carbon nanofibers, graphene and graphene nanoplates have shown benefits in improving the mechanical properties of polymer composites [101; 102]. Adding graphene to a polymer has been shown to result in effective EMI shielding properties as it has the capability to create conductive networks within the polymer matrix [103; 104; 105]. In addition to improved filler materials, polyaniline (PANI) comes as the matrix material [106]. [PERSON] et al. [107] evaluated EMI shielding properties by utilizing polymer blends of polyvinyl chloride (PVC) and PANI with graphene nanoplatelets (GNP) insertion. An enhanced electrical conductivity was noticed both for PVC/PANI and PVC/PANI/GNP composites. The EMI shielding effectiveness of 51 dB was achieved in the 18-20 GHz range. [PERSON] [108] used PANI and graphene nanoplatelet composite for microwave shielding applications. The composite was prepared keeping 1.5 mm thickness by using in-situ polymerization. It was revealed that with 10 wt.% loading of graphene nanoplatelet, high shielding effectiveness (up to 95%) was achieved in X-band frequency. Also, it was revealed that the high absorption occurs due to the dominant absorption mechanism. Having improved conductivity, better thermal stability, and excellent EMI shielding properties, the composite is recommended for its application in X-band microwave frequencies. [PERSON] et al. [109] formed TiO\({}_{2}\)/PANI/Graphene oxide (GO) composite via in-situ growth. The reflection loss was examined within the range of 2-18 GHz where the maximum came as \(-\)51.74 dB at 9.67 GHz frequency. [PERSON] et al. [110] used in-situ growth and hydrothermal method to synthesize magnetic graphene with PANI and porous TiO\({}_{2}\) and tested its EMI shielding efficiency within the range of 2-18 GHz. Keeping the sample thickness as 1.5 mm, a reflection loss of \(-\)45.4 dB was achieved. [PERSON] et al. [111] synthesized graphene@Fe\({}_{3}\)O\({}_{4}\)@PANI decorated with WO\({}_{3}\) particles by using a hydrothermal method and chemical oxidation polymerization. The spherical nanoparticles of Fe\({}_{3}\)O\({}_{4}\) and WO\({}_{3}\) having a diameter of 300-500 nm and 50-150 nm were spread in between graphene@PANI layers. The results showed that graphene@Fe\({}_{3}\)O\({}_{4}\)@PANI@WO\({}_{3}\) gives better electromagnetic wave absorption as compared to graphene@Fe\({}_{3}\)O\({}_{4}\) and graphene@Fe\({}_{3}\)O\({}_{4}\)@PANI, where maximum achieved absorption was \(-\)46.7 dB with a coating thickness of 4 mm. Whereas, the maximum absorbing bandwidth was \(\leq\)10 dB of 1.8 GHz (from 12.4 to 14.2 GHz) with a thickness of 1.5 mm. [PERSON] et al. [112] fabricated a graphene@Fe\({}_{3}\)O\({}_{4}\)@SiO\({}_{2}\)@polyaniline composite which gives better reflection loss of \(-\)40 dB at 12.5 GHz with 2.5 mm thickness and absorption bandwidth below \(-\)10 dB of 5.8 GHz (from 10.5 to 16.5 GHz) when compared with graphene@Fe\({}_{3}\)O\({}_{4}\). [PERSON] et al. [113] used the Hummers method to synthesized polyaniline (PANI), graphene oxide (GO) and Fe\({}_{3}\)O\({}_{4}\) as EMI shielding composite. With a sample thickness of 3.91 mm, a reflection loss of \(-\)53.5 dB was observed within the range of the 2-18 GHz frequency. In another study, PANI composite comprised of graphene and silver nanoparticles were used as EMI shielding material where the shielding effectiveness of 29.33 dB in 0.4-1.6 GHz frequency range was achieved at 5 wt.% loading [114]. [PERSON] et al. [115] formed Fe\({}_{3}\)O\({}_{4}\)/PANI rod/RGO composites to deal with the EMI which was tested under the range of 2-18 GHz where a reflection loss of \(-\)33.3 GHz was achieved. In the study, the material thickness was increased from 1 mm to 4 mm where the maximum reflection loss was achieved at 3.5 mm thickness.