Microwave Absorbing Properties of Acrylonitrile‐Butadiene‐Styrene/Graphene Nanoplatelet ( <scp>ABS</scp> / <scp>GNP</scp> ) Conducting Composites Obtained via Melt Mixing

ABSTRACT The rapid advancement of electronic devices has raised growing concerns about electromagnetic pollution, driving the demand for effective shielding materials. In response, polymer‐based conducting composites incorporating advanced fillers have gained significant research attention. In this study, acrylonitrile‐butadiene‐styrene (ABS) copolymer was used as the matrix, combined with varying amounts of graphene nanoplatelets (GNP), to develop lightweight, microwave‐absorbing materials with tunable properties. The composites were prepared via a melt‐mixing process, offering a scalable and industry‐relevant approach. A comprehensive characterization was performed, including rheological analysis, dynamic‐mechanical analysis, and AC electrical conductivity measurements. The electromagnetic interference shielding effectiveness (EMI SE) and microwave absorbing properties, quantified through reflection loss (RL), were investigated in the X‐band (8–12 GHz) and Ku‐band (12–18 GHz). Notably, the RL parameter, which is critical for elucidating the absorption‐dominated mechanism, has not been extensively studied in ABS/GNP systems, marking a significant novelty of this work. A sharp increase in AC conductivity with increasing GNP content indicated a percolation threshold at approximately 5 wt%. Remarkably, the composite containing 10 wt% GNP and 2 mm thickness demonstrated an RL of −17.5 dB at 8.8 GHz. Furthermore, optimal impedance matching, derived from dielectric measurements, corresponded to a thickness of 8 mm for the 5 wt% GNP composite, achieving an RL of −24.4 dB at 9.6 GHz and −19.8 dB at 16.7 GHz. For the 10 wt% GNP composite, effective absorption (−17 dB) was also maintained at 2 mm thickness at 8.9 GHz. These results highlight the potential of ABS/GNP composites as lightweight, cost‐effective, and tunable materials for microwave absorption and EMI shielding applications. The exploration of RL behavior in this system, particularly across multiple frequency bands, emphasizes the novelty and relevance of this research for application in the civil industry and stealth technology, the last one of great interest to the military industry to reduce the radar cross section.