Fast, non-carbonized, ambient-drying PVA/CNF@GO foam: Towards super-broadband microwave absorption and structural strength enhancement in aramid honeycomb

•PVA/CNF@14GO filled honeycomb composites at 30 mm achieve a broadband effective absorption performance of 13.25 GHz.•Honeycomb composites allows for broadband microwave absorption and enhanced structural strength.•The electromagnetic parameters of honeycomb composites can be precisely controlled.•The honeycomb composites were expected to be used for aviation stealth based on the light weight and broadband performance. Lightweight structural/microwave absorption (MA) integrated materials with broadband MA are urgently needed in the aerospace field. In this study, crosslinked PVA/CNF backbone-supported RGO foams were successfully filled into aramid honeycomb structures with significant broadband MA performance and structural enhancement properties through a synergistic strategy of chemical crosslinking, environmental drying and chemical vapor reduction. Flexible tuning of the electromagnetic parameters of the PVA/CNF@GO foam can be achieved by adjusting the number of GO parts. The 30 mm thickness of the PVA/CNF@14GO foam achieves a broadband effective absorption of 13.25 GHz, covering almost all C, X and Ku bands. Microstructural characterization and electromagnetic parameter tests proved that the uniform distribution of RGO was achieved with crosslinked PVA/CNF as the backbone, which resulted in less Debye relaxation and the construction of uniform conductive pathways. Therefore, the PVA/CNF@14GO-filled honeycomb not only enables the composite honeycomb to achieve broadband MA performance, but also achieves a compressive strength of 5.52 MPa, which is an improvement of 262.86 % with respect to that of the pure honeycomb. The obvious overlap of the CST power loss distribution and the electric field distribution region shows that the conductive loss and the 1/4 wavelength interference are the main paths for energy dissipation in the composite of the PVA/CNF@GO-filled honeycomb. The honeycomb-filled PVA/CNF@GO lightweight foams obtained in this chapter have good broadband microwave absorption properties and higher structural strength, which provide important design strategies and practical references for the development of high-performance MA-filled honeycomb structures.