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

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 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 wave-absorbing 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 energy 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.