# 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
While keeping the loading of CuNWs-TAGA as 7.2 wt.%, shielding effectiveness was achieved up to 47 dB in the X-band frequency range. [PERSON] et al. [141] synthesized RGO modified carbon fibre (RGO-CF) with the addition of epoxy (EP) using chemical reduction and electrophoretic deposition methods. With a thickness of 3-5 mm, the maximum shielding effectiveness of 37.6 dB was achieved within the X-band frequency range. [PERSON] et al. [142] synthesized 3D network porous graphene nanoplatelets (GNP) with Fe\({}_{3}\)O\({}_{4}\) and epoxy to form a shielding composite. With 7 wt.% loading of GNP and Fe\({}_{3}\)O\({}_{4}\), 37.03 dB shielding effectiveness was achieved in the X-band frequency range. A three-phase composite (graphite nanoplatelets (GNP)/carbonyl iron (Fe)/epoxy) was fabricated using a sonication method. The shielding effectiveness was evaluated from 1-67 GHz with various thickness and loadings. It was observed that with 5 mm thickness of the sample and 5 wt.% GNP loading, the reflection loss came as \(-78\) dB [143]. [PERSON] et al. [144] optimized thermally reduced graphene oxide (TGO), magnetic carbonyl iron (CI) and epoxy. The composite was tested in the X-band range where shielding effectiveness of 40 dB was achieved at 4 mm thickness. [PERSON] et al. [145] synthesized graphene carbon filler (GCF), with magnetic graphene (MG) and epoxy (EP) to form a shielding composite where GCF loading was 0.5 wt.% and MG loading was 9 wt.%. The testing range was from 18-26 GHz where shielding effectiveness of 51.1 dB was achieved. [PERSON] et al. [146] synthesized reduced graphene oxide and ferrite nanofiler with epoxy to form a shielding composite. While keeping the epoxy loading as 60 wt.%, a reflection loss of \(-\)10.26 dB was achieved with a 3 mm sample thickness in the 2-18 GHz frequency range. [PERSON] et al. [147] synthesized biodegradable multiphase polylactic acid with biochar and graphite using the hot-pressing method. The composite was tested within the frequency range of K-band where the shielding effectiveness was achieved as 30 dB while using the thin films of 0.25 mm thickness. Barium strontium titanate (BST) was synthesized with RGO and Fe\({}_{3}\)O\({}_{4}\) with the addition of polypyrrole polymer via chemical oxidative polymerization. The testing was made within the X-band frequency range where the shielding effectiveness of 48 dB was achieved [148]. Using the Hummers method, RGO and polyetherimide (PEI) polymer were synthesized to form a shielding composite that was tested in the range of X-band frequency. With the RGO loading of 2.5 wt.%, the maximum shielding effectiveness of 26 dB was achieved [149]. [PERSON] et al. [150] evaluated the anisotropic EMI shielding effectiveness of polymer-based composites. Magnetic responsive reduced graphene oxide (Fe\({}_{3}\)O\({}_{4}\)@RGO) as filler material was synthesized for controlling the orientation of reduced graphene oxide in thermoplastic polyurethane (TPU), where the magnetic field was applied to control the orientation of Fe\({}_{3}\)O\({}_{4}\)@RGO in in-plane and out-plane direction. A comparison was made between aligned Fe\({}_{3}\)O\({}_{4}\)@RGO/TPU, random Fe\({}_{3}\)O\({}_{4}\)@RGO/TPU and random RGO/TPU composites. Results revealed that the random Fe\({}_{3}\)O\({}_{4}\)@RGO/TPU composites shown an increase in EMI shielding effectiveness by 224% over random RGO/TPU composites. Whereas in-plane aligned Fe\({}_{3}\)O\({}_{4}\)@RGO showed 250% improved EMI shielding effectiveness over random RGO/TPU composites. The results proved that in determining the EMI shielding effectiveness, the orientation of fillers plays a vital role. [PERSON] et al. [151] synthesized graphene sponge (G) with polyurethane to form a shielding composite. With a sample thickness of 9 mm and graphene loading 18.7 wt.% shielding effectiveness of 35 dB was achieved in the X-band frequency range. In another study, TPU was synthesized with thermally reduced graphene nanosheets (TRG) via the solution blending method and was tested for its shielding efficiency in Ku-band.