Exploring the effect of graphene@Fe3O4 hybrid filler with TPU/PPy nanocomposites for microwave absorption in C, X, Ku bands with minimum reflection

The issue of electromagnetic (EM) radiation pollution is a significant concern in modern society, as it has negative impacts not only on electronic devices but also on the environment. The goal of this research is to fabricate TPU/PPy/gra@Fe nanocomposites via cost-effective solvent casting. The fabricated nanocomposites undergo structural and morphological characterization using FTIR, Raman, XRD, FESEM, HRTEM, and XPS. The dielectric, magnetic, and microwave absorption properties are investigated in the C, X, and Ku bands, i.e., 5–18 GHz. The dielectric and magnetic properties of nanocomposites are significantly enhanced by combining dielectric and magnetic fillers, such as gra@Fe, at appropriate weight ratios, as confirmed by the Cole-Cole plot. The total effectiveness (SE Tot ) of all nanocomposites across the microwave spectrum ranges from 22 to 37 dB. The SE Tot for TPU/PPy at a 1:3 gra@Fe ratio is 37 dB, accompanied by a SE Abs of 34 dB and a low SE Ref of less than 3 dB. The 95:5:1(1:3) composite exhibited SEₜₒₜ > 30 dB across 6.0–12.0 GHz (6.0 GHz effective bandwidth) and maintained SEₜₒₜ > 25 dB within the Ku band (12–17 GHz), corresponding to an effective bandwidth of approximately 5 GHz. All microwave nanocomposites exhibit a reflection rate below 20%. Importantly, the reflection rate of TPU/PPy 1:3 gra@Fe nanocomposite is less than 10% in the X and Ku bands. The TPU/PPy/gra@Fe nanocomposite exhibits a low reflection rate and broadband performance, rendering it suitable for microwave and radar-absorption applications, especially in the military field.