Influence of GNP and MWCNTs Fillers in Hybrid Polymer Nanocomposite on the Microwave Absorption Performance of Multilayered Structures

Electromagnetic wave-absorbing materials are crucial for attenuating electromagnetic waves in aerospace and electronic communications. Conventional materials often lack mechanical robustness and lightweight applications. To improve performance, multilayer absorbing coatings are developed using polymer nanocomposites containing multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs). In the present work, non-sorted genetic algorithm II (NSGA II) is employed to construct 21 composites with varying weight fractions of polypropylene (PP)-GNP and PP-MWCNT nanocomposites. The study presents the variations in real (ɛ_r’) and imaginary (ɛ_r”) parts of relative permittivity for different weight percentages of PP/epoxy and PP/GNP/epoxy composites in the X-band frequency range. The real permittivity of graphene/epoxy and PU/graphene/epoxy composites remains relatively constant with increasing frequency, while the GNP-PP-epoxy composite shows a variation from 3.9 to 6.2, peaking at 2.7% GNP in the 8.2 – 12.4 GHz range due to enhanced electrical conductivity and polarization effects. The optimal two-layer model, consisting of 1.5% MWCNT/PP/epoxy and 2.7% GNP/PP/epoxy, exhibited exceptional absorption performance with a minimum reflection loss of − 21 dB and a qualified bandwidth of 4.2 GHz. The optimized structure undergoes thorough experimental validation to confirm its practical applicability. This measurement offers insights into the material’s absorption efficiency and impedance matching, with experimental RL values compared to the theoretically optimized results. This design integrates material functionality and structural design, enabling effective absorption across a wide frequency range.