With the rapid advancement of electronic an‎d telecommunication technologies, electromagnetic wave pollution has emerged as a significant challenge, as the interference caused by these waves can disrupt device performance an‎d adversely affect human health. In this context, the development of high-performance protective materials for the absorption an‎d attenuation of electromagnetic waves is of critical importance. To investigate the shielding properties of different generations of protective materials, aluminum (a conductive metal), chromium (a magnetic metal), graphite (a carbon allotrope), an‎d titanium carbide-based ceramic compounds, as well as Cr- an‎d Ti-based MAX an‎d MXene phases representing advanced nanomaterials, were systematically examined. Initially, Cr₂AlC was synthesized from industrial-grade graphite an‎d cellulose-derived activated carbon using the MA-SHS method, an‎d Cr₂CTₓ MXene was subsequently obtained via selec‎tive etching. Similarly, Ti₃C₂Tₓ MXene was synthesized from industrial Ti₃AlC₂. The etching process was optimized by controlling parameters such as time, temperature, an‎d solvent type to produce stable two-dimensional structures with high electrical conductivity an‎d efficient electromagnetic wave absorption capabilities. For protective performance eva‎luation, the nanostructures were deposited onto PAN nanofiber mats, with optimized coating conditions comprising a 2 wt% nanostructure dispersion an‎d a double-layer thermal pressing procedure. Furthermore, the binder-free san‎dwich nanofiber structure stabilized the particles, enhanced distribution uniformity, an‎d significantly improved shielding performance. The results indicated that among the four generations of protective materials, the optimized graphite sample exhibited a relative shielding effectiveness of approximately 2.55 dB·mm⁻¹, an‎d its electrothermal response under 12 V allowed it to reach temperatures of around 62 °C. Comparative analysis of the corresponding MAX an‎d MXene phases demonstrated that MXenes, due to their two-dimensional sheet-like structures, higher specific surface area, an‎d deeper penetration into the nanofiber layers, provided markedly superior shielding performance, while the difference between Ti₃AlC₂ an‎d Cr₂AlC remained within a reasonable range of less than 1 dB. These findings underscore the importance of two-dimensional structural design an‎d precise control of nanostructure dimensions for achieving stable an‎d efficient protective coatings. Additionally, Ti₃C₂Tₓ MXene exhibited enhanced protective performance due to its smaller dimensions, higher penetration into the nanofiber bulk, an‎d maintained interlayer contact, with the optimized graphite-based sample achieving a relative shielding effectiveness of approximately 2.55 dB·mm⁻¹.

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غلامرضا عسكري

اكبر خدامي , حسين توانايي