Poly(di-allyl phthalate) hybrid nanocomposites with magnetic conductive coupling for absorption dominated EMI shielding.

Electromagnetic interference (EMI) remains a critical challenge for modern electronic systems, driving the need for lightweight materials with efficient shielding capabilities. In this work, Fe3O4@RGO hybrid nano-fillers were synthesized via a co-precipitation route and incorporated into a poly(di-allyl phthalate) (PDAP) matrix to produce composite films with tunable dielectric-magnetic coupling. Structural analyses confirmed the uniform decoration of Fe3O4 nanoparticles on RGO sheets and their homogeneous dispersion within the PDAP network. The calculated electromagnetic parameters (ε' ≈ 12, ε″ ≈ 4, µ' ≈ 1.3, µ″ ≈ 0.3 at 10 GHz) reveal strong dielectric and magnetic loss channels that support an absorption-dominated shielding mechanism. The optimal composite (PMR20) achieved a total shielding effectiveness of ~ 31.5 dB across the X-band, corresponding to > 99.9% attenuation of incident radiation, with SEA contributing the major portion of the overall SE. The synergy between conductive RGO pathways, magnetic relaxation of Fe3O4, and interfacial polarization within PDAP underpins the enhanced attenuation behavior. This study demonstrates PDAP as a promising and underexplored thermosetting host for hybrid EMI shielding materials, offering a platform for lightweight and high-performance electromagnetic protection.