Role of Magnetic NiFe 2 O 4 and Conductive rGO in Tailoring the Dielectric and EMI Shielding Properties of TPU Nanocomposite Films

ABSTRACT Thermoplastic polyurethane (TPU)‐based polymer nanocomposites (PNCs) reinforced with reduced graphene oxide (rGO) and nickel ferrite (NiFe 2 O 4 ) nanoparticles were fabricated via a solution casting followed by compression molding. The homogeneous dispersion of rGO sheets and NiFe 2 O 4 nanoparticles within the TPU matrix created multiple heterogeneous interfaces, which facilitated interfacial polarization and magnetic loss mechanisms. Owing to these synergistic effects, the TPU/rGO/NiFe 2 O 4 composite where 5 wt% fixed loading of NiFe 2 O 4 with rGO loading 20 wt% (T‐R20‐N5) exhibited excellent electromagnetic interference (EMI) shielding effectiveness across the X‐band (8.2–12.4 GHz), achieving a maximum total shielding of approximately 20 dB with a low reflection loss of ~3 dB, dominated by absorption. The dielectric constant ( ε ′) reached ~450, indicating enhanced charge transport and interfacial polarization. Furthermore, the nanocomposite demonstrated superior mechanical strength, with a tensile stress of 27 MPa, attributed to efficient stress transfer through the interconnected rGO‐NiFe 2 O 4 network. These results highlight the potential of TPU/rGO/NiFe 2 O 4 nanocomposites as lightweight, flexible, and broadband EMI shielding materials combining high dielectric performance, strong mechanical resilience, and low reflection—suitable for next‐generation aerospace, electronics, and wearable applications.