Fabrication and evaluation of thin layer PVDF composites using MWCNT reinforcement: Mechanical, electrical and enhanced electromagnetic interference shielding properties

B V Bhaskara Rao,B S Kothavale,Nikita Kale,S N Kale

doi:10.1063/1.4953810

Abstract

Radar X-band electromagnetic interference shielding (EMS) is one of the prime requirements for any air vehicle coating; with limitations on the balance between strength and thickness of the EMS material. Nanocomposite of multiwalled-carbon-nanotubes (MWCNT) has been homogeneously integrated (0 – 9 wt%) with polymer, poly (vinylidene fluoride, PVDF) to yield 300 micron film. The PVDF + 9 wt% MWCNT sample of density 1.41 g/cm3 show specific shielding effectiveness (SSE) of 17.7 dB/(g/cm3) (99.6% EMS), with maintained hardness and improved conductivity. With multilayer stacking (900 microns) of these films of density 1.37 g/cm3, the sample showed increase in SSE to 23.3 dB/(g/cm3) (99.93% EMS). Uniform dispersion of MWCNTs in the PVDF matrix gives rise to increased conductivity in the sample beyond 5 wt% MWCNT reinforcement. The results are correlated to the hardness, reflection loss, absorption loss, percolation threshold, permittivity and the conductivity data. An extremely thin film with maximum EMS property is hence proposed.

Highlights

Carbon-based materials are most intriguing materials for researchers in recent times
Carbon black, carbon fibers, carbon nanofibers, carbon nanotubes have been extensively investigated in this context, for electromagnetic interference shielding (EMS) owing to their unique combination of electrical conduction, polymeric flexibility, and light weight.[1,2,3,4,5]
The efficiency as high as 99.65% (25 dB) has been observed with single film, which increased to 99.96% (32 dB) with 3 layers of such films, stacked together. These values are highest as reported up-till for the films as thin as 300 microns for EMS applications, without compromising the mechanical strength of the materials

Summary

Introduction

Carbon-based materials are most intriguing materials for researchers in recent times Their various forms and types have caught attention due to their exotic properties which find applications in various domains right from sensors to textiles, pharmaceuticals, intelligent coatings and biomedical applications. Though there has been immense progress done in this particular domain, the materials developed have had some limitations, on one side; and the applications have posed newer challenges, on the other Materials such as graphite, carbon black, carbon fibers, carbon nanofibers, carbon nanotubes have been extensively investigated in this context, for EMS owing to their unique combination of electrical conduction, polymeric flexibility, and light weight.[1,2,3,4,5] Interesting theories have been put forth by the researchers to explain the normal and anomalous behavior of carbon-based materials in the various polymer matrices.

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Conclusion