# 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
It proves that by increasing the sample thickness the shielding effectiveness can be increased but up to a certain level. [PERSON] et al. [116] synthesized graphene@NiO@PANI@Ag using hydrothermal and in-situ growth method. The composite material was tested within the range of 2-18 GHz where a reflection loss was achieved as \(-37.5\) dB with 3.5 mm sample thickness. [PERSON] et al. [117] formed graphene-doped polyaniline (G-PANI) as shielding composite via in-situ growth. The shielding effectiveness of 32.5 dB was achieved within the range of 2-18 GHz with 1.5 mm thickness. [PERSON] et al. [118] formed a new material \(\gamma\)-Fe\({}_{2}\)O\({}_{3}\) and decorated it with RGO and PANI to observe the shielding efficiency of the composite. The composite was formed via chemical oxidation polymerization and in-situ growth and tested within the X-band frequency range. While keeping the sample thickness as 2.5 mm, total shielding effectiveness of 51 dB was achieved. [PERSON] et al. [119] explored Ti\({}_{3}\)C\({}_{2}\)T\({}_{\rm x}\) MXene shielding properties by making its composite with Fe\({}_{3}\)O\({}_{4}\) and PANI polymer. The co-precipitation method was used to prepare the composite and was tested within the X-band frequency range. Shielding effectiveness of 58.8 dB was achieved with 12.1 \(\upmu\)m sample thickness. [PERSON] et al. [120] used the citrate precursor method to synthesize RGO, barium ferrite (BF) and PANI to form a shielding composite where shielding effectiveness of 31.1 dB was achieved in the X-band frequency range. [PERSON] et al. [121] synthesized PANI/Li\({}_{0.5}\)Fe\({}_{0.5-x}\)Gd\({}_{x}\)O\({}_{4}\) via in-situ growth where the composite was tested within the X-band frequency range. Keeping the sample thickness as 0.2 mm, shielding effectiveness of 42 dB was achieved. [PERSON] et al. [99] evaluated ultra-efficient electromagnetic interference shielding by using reduced graphene oxide and polystyrene. The results showed that with 3.47 vol% of RGO-based polymer composite, 45.1 dB shielding effectiveness was achieved. [PERSON] et al. [122] formed two different composites via a hot compressed method. One was segregated RGO with polystyrene (PS) and the other was conventional RGO/PS. The testing was made from 0-20 GHz where the shielding effectiveness of 29.7 dB and 14.2 dB was achieved with 2 mm sample thickness. [PERSON] et al. [123] formed a composite by optimizing polycarbonate and graphene nanoplatelets (GNP), using the facile solution method, for electromagnetic interference shielding in X-band. Keeping the composite thickness as 1 mm, 35 dB shielding effectiveness was achieved, where, by increasing the thickness up to 2 mm, 47 dB shielding effectiveness was achieved, indicating that the increase in the thickness directly enhances the shielding effectiveness. [PERSON] et al. [124] examined lightweight high-density polyethylene (HDPE) with graphene nanoplatelets composites which were fabricated using the supercritical fluid and injection moulding process. The shielding effectiveness of 31.6 dB was achieved in K-band. [PERSON] et al. [125] fabricated ethylene propylene diene monomer rubber (EPDM) with graphene nanoplatelets loading to observed EMI shielding effectiveness in X-band and Ku-band. The results showed that with 8 wt.% of GNP, keeping thickness 0.3 mm, 33 dB shielding effectiveness was achieved in X-band, whereas, in Ku-band, 35 dB shielding effectiveness was achieved. [PERSON] et al. [126] conducted a study on sub-terahertz radiation shielding by using a graphene-based plastic absorber where PDMS polymer was used. It was observed that being lightweight and nonconductive, graphene-based composites can absorb 99.99% of electromagnetic waves, whereas most metal-based composites simply redirect the radiations. [PERSON] et al. [127] formed a copper-coated RGO@PDMS polymer composite by the Hummers method, where a shielding effectiveness of 74.2 dB was achieved in the X-band frequency range. [PERSON] et al.