Influence of <scp>rGO</scp>@<scp>CNT</scp>@<scp>Fe₃O₄</scp>@ Poly (An‐co‐M) Nanofiller Modification on the Microwave Absorption Characteristics of Epoxy‐Based Nanocomposite

ABSTRACT With electromagnetic (EM) pollution on the rise, there is a growing need for high‐performance absorbing materials. Current absorbers often fall short, failing to balance strong absorption with a wide range of frequencies. In the current work, the reduced‐graphene oxide@ carbon nanotube@ magnetic iron oxide@ poly (aniline‐co‐Melamine) (rGO@CNT@Fe 3 O 4 @ poly [An‐co‐M]) as a novel EM wave absorbing nanofiller was prepared. The analysis of the prepared nanofillers at various stages of synthesis, including rGO@CNT, rGO@CNT@Fe 3 O 4 , and rGO@CNT@Fe 3 O 4 @ poly (An‐co‐M), was conducted using several characterization methods such as Fourier transform infrared spectroscopy (FTIR), x‐ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and value stream mapping (VSM). Different nanofillers were utilized to construct epoxy‐based nanocomposites, and their EM absorber performances, including complex permittivity ( ε r ), permeability ( μ r ), and reflection loss (RL), were evaluated. Next, the effect of various parameters, such as nanofiller concentration, EM absorber type, and the molar ratio of aniline to melamine (An:M) in the poly(An‐co‐M) shell, on the EM absorption properties of epoxy‐based nanocomposites was studied. The optimal An: M molar ratio in the poly(An‐co‐M) shell was determined to be 3:1 with a nanofiller content of 5.0 wt%. According to the vector network analyzer (VNA) test results, among the pure epoxy and other prepared epoxy‐based nanocomposites, the epoxy‐based nanocomposite modified with rGO@CNT@Fe 3 O 4 @ poly (An‐co‐M) nanofiller exhibits better absorption properties, which is attributed to the combination of dielectric and magnetic losses of the nanofiller. The study indicated that the rGO@CNT@Fe 3 O 4 @ poly (An‐co‐M) epoxy‐based nanocomposite, referred to as the S‐4 sample, achieved an optimum RL of −17.0 dB and an absorption bandwidth of &gt; 3 GHz at a matched thickness of 5.0 mm. Taking into account the more excellent EM absorption behavior of rGO@CNT@Fe 3 O 4 @ poly (An‐co‐M) incorporated epoxy nanocomposite, the poly(An‐co‐M) coating on the rGO@CNT@Fe 3 O 4 nanofiller is an effective strategy for constructing a high‐efficiency EM absorber.