Effect of different proportions of CNTs/Fe₃O₄ hybrid filler on the morphological, electrical and electromagnetic interference shielding properties of poly(lactic acid) nanocomposites

Abstract Due to the shortage of petroleum resources, poly(lactic acid) (PLA), a biodegradable polymer, has been widely considered as replacement for traditional petroleum-based polymers. Therefore, multifunctional PLA composites have become increasingly popular. In this study, conductive carbon nanotubes (CNTs) and magnetic nano-Fe 3 O 4 fillers were melt-blended with PLA. The impact CNTs composition on electrical electromagnetic interference (EMI) shielding properties nanocomposites was investigated in detail by adjusting CNTs-to-nano-Fe ratio. When hybrid filler content fixed at 10 wt%, conductivity results indicated that addition single could effectively improve nanocomposites, while contribution hardly noted. A suitable ratio can yield excellent synergistic effects EMI properties. containing 50:50 exhibited (90.6 S·m −1 ) effectiveness (EMI SE ∼ 40.5 dB). This is primarily because provide good conductivity, but provides additional interfacial polarization eddy current losses caused its dielectric These synergistically result an impedance mismatch, loss, relaxation composite materials, improving against waves. Further, it found changing also affected wave absorption. CNT-to-nano-Fe 25:75, had 24.6 dB, absorptivity reach maximum (40.3%). Thus, study valuable reference preparing polymer constructing networks.