Fabrication of lightweight multifunctional microwave-absorbing composites with load-bearing and infrared stealth capabilities using a modified 3D integrated hollow E-glass fiber

Abstract

Achieving both lightweight and high load-bearing capacity in microwave-absorbing materials remains a significant challenge. Inspired by structural composites and aerogels, a multi-cavity, aerogel-like structure is developed by incorporating modified insulation cavities (hollow glass microsphere@Ni) within an epoxy resin matrix. This composite is embedded into the centimeter-scale cavities of 3D integrated hollow E-glass fibers to design a lightweight, high-strength microwave-absorbing material, addressing the contradiction between weight reduction and load-bearing capability. The special structure and impedance gradient matching design induce multiple reflections and scattering of microwave, which endows the composite with excellent impedance matching and a wide effective absorption bandwidth (EAB) of 11.65 GHz. In terms of mechanics, the synergistic effect of the Ni(OH)₂ interface-modified E-glass fiber and aerogel-like structure filling increases its three-point bending mechanical strength by an order of magnitude (from 4.64 MPa to 88.05 MPa) and provides excellent load-bearing capacity. In addition, the special structural design enables the composite to exhibit good temperature regulation function, producing a temperature drop of 142.1 °C at 360.0 °C and realizing infrared stealth performance in medium- and low-temperature environments. This paper thus presents a strategy for developing economical, lightweight, microwave-absorbing, and load-bearing integrated multifunctional composites for future applications.