Combination effect of functionalized high aspect ratio carbonaceous nanofillers and carbon black on electrical, thermal conductivity, dielectric and EMI shielding behavior of co-continuous thermoplastic elastomeric blend composite films

Abstract

The utilization of conductive hybrid carbonaceous fillers to fabricate highly efficient electromagnetic interference (EMI) shielding materials has become a popular area of research interest recently. Here, we report the facile fabrication of lightweight thermoplastic elastomeric blend composite films by solution mixing technique, taking advantage of both the hybrid carbonic nanofillers (high aspect ratio carbon inclusion and conductive carbon black) and the co-continuous polystyrene (PS)/ethylene-co-methyl acrylate (EMA) blend. Combination of acid-functionalized multiwalled carbon nanotubes (f-CNT) and carbon nanofibers (f-CNF) with conductive Vulcan-XC 72 carbon black (VCB) aids in the more uniform dispersion of hybrid carbonaceous inclusion in this blend system. The selective location of hybrid nanofillers in EMA phase of binary polymer mix enhanced the electrical properties, thermal conductivity, and microwave shielding performance of the resultant blend composites by constructing a dense, co-supportive, double percolated conductive network throughout the blend. The effect of f-CNT or f-CNF concentration in hybrid composites on the above-mentioned properties of blend composites has been investigated in this work. The as-prepared PS/EMA/VCB/f-CNT and PS/EMA/VCB/f-CNF blend composite films exhibited a thermal conductivity of 0.81 and 0.83 W/m.K and absorption-dominated microwave shielding of -31 and -32.5 dB, respectively with 15 wt% hybrid filler loading containing 50 wt% of f-CNT or f-CNF. These conductive thermal management composite films could be excellent choices to mitigate EM pollution.