Magnetic isocyanate-based polyimide composite foam for efficient microwave absorption

Developing and fabricating high-performance microwave absorption materials with excellent comprehensive properties becomes an urgent necessity. In this work, a facile magnetic isocyanate-based polyimide foam with strong interfacial interaction is fabricated by vacuum-impregnating carbon nanotube (CNT)/anisotropic iron flake polyamide acid (PAA)-suspension on the surface of the skeleton. The successful loading of conductive CNT and anisotropic iron flake can facilitate the optimization of impedance matching and the generation of multiple loss mechanisms in foam, endowing it with an efficient microwave absorption performance. More importantly, self-enhancement effect of PAA as the precursor of polyimide significantly reinforces the interfacial interaction between foam and CNT/anisotropic iron flake, due to the similar molecular structure with the isocyanate-based polyimide. The strong interfacial interaction combined with their intrinsic properties further contributes to the improvement of stability and durability, such as high/low-temperature, corrosion, and flame resistance. Therefore, such excellent comprehensive performance makes it possible to become a promising defense material to be applied in harsh marine environments. A facile magnetic isocyanate-based polyimide foam with strong interfacial interaction by vacuum-impregnating CNT/anisotropic iron flake polyamide acid-suspension on the surface of the skeleton. The successful loading of conductive CNT and anisotropic iron flake facilitates the optimization of impedance matching and the generation of multiple loss mechanisms, endowing it with an efficient microwave absorption performance. Importantly, self-enhancement effect of polyimide significantly reinforces the interfacial interaction, making it possible to become a promising defense material to be applied in harsh marine environment. [Display omitted] •A facile magnetic foam with strong interfacial interaction is fabricated.•Loading CNT and ZAF-5 on skeleton promotes the formation of hierarchical impedance.•Hierarchical impedance structure facilitates entrance and dissipation of EMW.•Strong interfacial interaction accelerates improvement of stability for composite.