Authors Sushmita, K. ; Formanek, P. ; Krause, B. ; Pötschke, P. ; Bose, S.
Title Distribution of carbon nanotubes in polycarbonate-based blends for electromagnetic interference shielding
Date 10.01.2022
Number 59728
Abstract In a quest to understand the key role of functionalization of carbon nanotubes (CNTs) and their distribution in polymer matrices or polymer blends on the electromagnetic interference (EMI) shielding performance of the resulting nanocomposites, a library of polycarbonate (PC)-based nanocomposites was prepared via the melt mixing process. To introduce structural defects in CNTs and harness suitable functional groups that can facilitate interactions with the host polymer, CNTs were ball-milled followed by mixing with PC and PC/PVDF (polyvinylidene fluoride) blends. These composites were evaluated for their morphology, bulk electrical conductivity, and total EMI shielding effectiveness (SET) and compared with composites with pristine CNTs. Compartmentalization of CNTs or ball-milled CNTs (localized in PC component) was observed in PC/PVDF-based blend composites. This study further highlights the role of a compatibilizer, PMMA (poly(methyl methacrylate)), in the final properties of the blend nanocomposites. Also, in selected cases, hybrid reduced-graphene-oxide/Fe3O4 nanoparticles were used as a second filler to increase thermal conductivity. Through the study, it is well understood that composites containing ball-milled CNTs, though they showed a decrease in electrical conductivity (compared to pristine CNT-based composites), need not necessarily lead to a drastic decrease in SET unless the length is too short on account of the ball milling. Obviously, the defects generated in ball-milled CNTs on their surface play a crucial role in improving the shielding performance. The CNT compartmentalization (in the PC component), though improved the electrical conductivity compared to single matrix composites, is not the sole deciding factor in enhancing the SET. Instead, the CNT state, dispersion, and distribution in combination play a significant role in deciding the final properties of the composites. Interestingly, although the addition of PMMA refines the blend morphology, it does not prove to be an effective solution for enhancing shielding performance.
Publisher ACS Applied Nano Materials
Citation ACS Applied Nano Materials 5 (2022) 662-677

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