Electromagnetic Shielding Effectiveness of Glass Fiber/Epoxy Laminated Composites with Multi-Scale Reinforcements

Nilufar Yesmin,Vijaya Chalivendra

doi:10.3390/jcs5080204

Nilufar Yesmin, Vijaya Chalivendra

Open Access

https://doi.org/10.3390/jcs5080204

Copy DOI

Abstract

In this study, an experimental investigation has been performed to understand the electromagnetic interference-shielding effectiveness (EMI-SE) of glass fiber/epoxy laminated composites embedded with carbon nanotubes (CNTs) and Fe3O4 nanoparticles, reinforced with micro carbon fibers along the thickness direction. Micro carbon fibers were reinforced along the thickness direction between the laminates using an electro-flocking process and a vacuum infusion process used to fabricate the composites. The EMI-SE of the composites was measured in the X-band frequency range (8–12 GHz). The effect of carbon fibers of three different lengths (80 µm, 150 µm, and 350 µm) with two different fiber densities (1000 and 2000 fibers/mm2) and two different amounts of Fe3O4 nanoparticles (0.5 and 1 wt.%) on total SE, absorption, and reflection was investigated. Due to the synergetic effect of Fe3O4 nanoparticles, CNTs, and carbon fibers, the final EMI shielding of the composites was mainly dominated by the absorption process. The absorption was more pronounced in the composites of longer carbon fibers with improved electrical conductivity. The presence of Fe3O4 nanoparticles also enhanced total SE values with improved magnetic permeability. The composite with micro carbon fibers of 350 µm length and 2000 fibers/mm2 density with 1 wt.% of Fe3O4 nanoparticles showed the maximum value of total SE.

Highlights

Electromagnetic shielding (EMS) is often used to cut down emissions or enhance the protection of electronic equipment
Multi-walled carbon nanotubes (MWCNTs) having an external diameter of 20–30 nm, internal diameter of 5–10 nm, length of 10–30 μm, and purity greater than 95% was supplied by Cheap Tubes Inc., Cambridgeport, VT, USA
SE due to Absorption (SEA), and SE due to Reflection (SER) demonstrated higher values as the carbon fiber length increases from 80 μm 2 of all three carbon fiber lengths without Fe3O4 nano parfibers/mm

Summary

Introduction

Electromagnetic shielding (EMS) is often used to cut down emissions or enhance the protection of electronic equipment. Enclosures of electronic equipment were produced using highly conducting metal to accomplish the required shielding. Design constraints called for reducing the weight of electronic devices with conducting polymers and composites [1,2,3,4]. There have been several studies on the use of polymer composites to enhance EMS for the last decade. Researchers investigated the effects of various reinforcements on the EMS of the polymer composites. Jou et al [5] investigated the electromagnetic shielding effectiveness (SE) of carbon nanotubes (CNTs) embedded polymers. The authors studied the use of CNTs of two different aspect ratios of 500 and

Methods

Results

Conclusion