Magnetically enhanced 3D carbon nanomaterials and TPU composites for efficient microwave absorption and EMI shielding

This study investigates the integration of magnetic functionality into hybrid 3D carbonaceous nanofillers by grafting iron (Fe) and nickel (Ni) nanoparticles, producing Fe-3D and Ni-3D nanomaterials. Their microstructural features and microwave absorption behavior were examined to assess their suitability for electromagnetic interference (EMI) shielding. Fe-3D demonstrates superior EMI shielding effectiveness (28 dB) due to its higher electrical conductivity (16 S/m), while Ni-3D reaches 22 dB with lower conductivity (8 S/m). The aspect ratio, dispersion quality, and concentration of the nanofillers strongly influence the shielding performance of TPU-based nanocomposites. Optimal dispersion occurs at 5 wt% loading using solution casting, whereas higher loadings (10-20 wt%) cause agglomeration and FLG restacking. TPU/Fe-3D nanocomposites outperform TPU/Ni-3D, and at 20 wt% both exceed the minimum 10 dB EMI shielding requirement, confirming their promise as effective materials for microwave absorption and electromagnetic protection.