Multilevel structural modified 3D integrated hollow E-glass fabric manufacture lightweight electromagnetic wave absorbing/load bearing multifunctional composite

The compatibility of lightweight and high load bearing remains rather challenging in the research of multifunctional electromagnetic wave (EMW) absorbing composite. Herein, a multilevel structural engineering strategy is developed by grafting carboxylated multi-walled carbon nanotubes (MWCNT-COOH) to the E-glass fiber using dopamine and constructing the conductive bridges by Ag nanoroads, further integrating a multi-cavity structure using hollow glass microsphere (HGM)@MWCNT-COOH/epoxy resin within the 3D cavities of E-glass fabric, solving the insufficient mechanical properties of the lightweight EMW absorbing composite. Compared with the original 3D integrated hollow E-glass fiber-reinforced epoxy composite, the bending strength has increased by nearly an order of magnitude: from 17.05 MPa to 105.85 MPa. An effective absorbing bandwidth of 6.42 GHz with reflection loss < −5 dB was achieved at a thicknesses of 4.0 mm, attributed to the construction of rich heterogeneous interfaces and conductive bridges. Furthermore, the composite modulates temperature to hide infrared radiation, with a temperature drop (ΔT) of 120.9 °C at 360 °C, thanks to its unique material and thermal insulation cavity@rich network structure design. It is expected to provide theoretical guidance for the preparation of a multifunctional composite with EMW absorbing, load-bearing, and infrared stealth capabilities.