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.