Engineering Scalable and Cost-Effective Fabrication of Architecturally Tailored Boron Nitride-Epoxy-Silane-Functionalized Cardanol Nanocomposites for Advanced Microwave Absorption Applications

The increasing prevalence of electronic devices and 5G technology has exacerbated electromagnetic wave (EMW) pollution, necessitating effective countermeasures. Microwave-absorbing materials (MAM) offer promising solutions to address this issue. Owing to its exceptional dielectric properties, low density, thermal conductivity, and chemical stability, boron nitride (BN) is a suitable candidate for MAM development. This study investigates the optimization of the BN microwave absorption performance through nanocomposite fabrication. The composite has been engineered with enhanced polarization and improved interfacial interactions by incorporating BN into an epoxy resin matrix modified with silane-functionalized cardanol. The resulting material exhibited superior surface roughness and hydrophobicity. The optimal composite formulation demonstrated outstanding microwave absorption properties, achieving a reflection loss of −23 dB at 12.4 GHz with a thickness of only 10 mm. Furthermore, the composite displayed an enhanced mechanical damping value of 0.85. These results suggest that the synergistic effect of impedance matching and multiple polarization loss mechanisms within the composite structure contributes to its superior microwave absorption performance.