Multifunctional epoxy composites enabled by a three-dimensional MOF-derived carbon network for electromagnetic wave absorption and fire safety

With the rapid development of high-frequency and high-power-density electronic devices, epoxy-based packaging materials are increasingly required to address electromagnetic interference and fire-safety concerns while maintaining acceptable heat-spreading capability. However, conventional epoxy resin (EP) suffers from intrinsically low thermal conductivity, weak electromagnetic wave absorption (EMA), and high flammability, making multifunctional integration highly challenging. Herein, a multifunctional epoxy composite enabled by a three-dimensional (3D) MOF-derived carbon network is rationally designed. A Co/Zn-based zeolitic imidazolate framework was deposited on a melamine foam scaffold and subsequently carbonized to construct an interconnected CMF@Co/Zn-NC network. The resulting 3D architecture provides continuous conductive pathways, abundant heterogeneous interfaces, and defect-rich carbon domains, which regulate dielectric properties and impedance matching. Consequently, the CMF@Co/Zn-NC/EP composite with 10 wt% filler exhibits strong EMA performance, achieving a minimum reflection loss of −56.79 dB at 1.92 mm and a maximum effective absorption bandwidth of 7.56 GHz at 1.97 mm. Electromagnetic attenuation is mainly associated with dielectric loss mechanisms, including conductive loss, interfacial polarization, and dipolar polarization, while magnetic loss plays a secondary role. In addition, the interconnected carbon framework moderately improves the thermal transport of EP, increasing the thermal conductivity from 0.18 to 0.34 W m⁻¹ K⁻¹. Cone calorimetry results demonstrate improved fire safety, with the peak heat release rate, total heat release, and smoke production rate reduced by 55.9%, 20.9%, and 43.9%, respectively, relative to neat EP. This work provides a structural design strategy for multifunctional epoxy composites integrating electromagnetic attenuation, improved fire safety, and moderately enhanced heat-spreading behavior.