We report the electrical, mechanical and electromagnetic interference (EMI) shielding performance of polypropylene random copolymer (PPR)/multi-wall carbon nanotube (MWCNT) nanocomposites enabled via customized fused filament fabrication process. The electro-conductive PPR/MWCNT filament feedstocks were fabricated via shear-induced melt-blending process that allows 3D printing of nanoengineered composites even at higher MWCNT loading (up to 8 wt%). The uniform dispersion of MWCNTs in PPR matrix confirmed via Raman spectroscopy and scanning electron microscopy facilitates better mechanical, electrical and EMI shielding performance. The results furthermore show enhanced shielding properties and higher attenuation for the nanocomposites printed in 90° direction (~ − 37 dB for 8 wt% MWCNT loading). Effective interfacial adhesion between the beads with lesser extent of voids (confirmed via micro-computed tomography) endorsed low transmission loss in nanocomposites printed in 90° direction compared to samples printed in 0° direction. Surface architected structure (frustum shape) reveals higher specific shielding effectiveness (maximum ~ − 40 dBg−1cm3, + 38%) over the plain structure. The realization of excellent shielding effectiveness (~ 99.9% attenuation) of additive manufacturing-enabled PPR/MWCNT nanocomposites demonstrates their potential for lightweight and strong EMI shields.
Graphical Abstract
The production of an innovative, high-performance graphene-based polymer nanocomposite using cost-effective techniques was pursued in this study. Well-dispersed and uniformly distributed graphene platelets within a polymer matrix, with strong interfacial bonding between the platelets and the matrix, provided an optimal nanocomposite system for industrial interest. This study reports on the reinforcement of high molecular weight multimodal-high-density polyethylene reinforced by a microwave-induced plasma graphene, using melt intercalation. The tailored process included designing a suitable screw configuration, paired with coordinating extruder conditions and blending techniques. This enabled the polymer to sufficiently degrade, predominantly through thermomechanical-degradation, as well as thermo-oxidative degradation, which subsequently created a suitable medium for the graphene sheets to disperse readily and distribute evenly within the polymer matrix. Different microscopy techniques were employed to prove the effectiveness. This was then qualitatively assessed by Raman spectroscopy, X-ray diffraction, rheology, mechanical testing, density measurements, thermal expansion, and thermogravimetric analysis, confirming both the originality as well as the effectiveness of the process.
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