Unprecedented Electromagnetic Shielding Effectiveness of Lightweight Nonwoven Ag/PA66 Fabrics

Abstract

Novel, high-performance silver coated polyamide, Ag/PA66, nonwoven fabrics with a density of only 0.04g/cm 3 have been developed using staple fibres of 19 (3.3dtex) and 27 (6.7dtex) μm diameter.The obtained nonwoven fabrics with an Ag loading of 12-18wt% exhibited excellent weight-normalised specific electromagnetic shielding effectiveness of over 1200 dB/(g/cm 3 ) in the 0.015-3GHz range, which is among the highest reported till date. Moreover, the applied microwave was verified to be absorbed rather than being reflected back making the fabrics highly suitable for shielding applications.It was also observed that nonwoven fabrics made from finer 3.3dtex Ag/PA66 fibres have higher reflection and lower absorption values than their thicker (6.7dtex) counterparts. Additionally, we have also explored the use of these nonwoven Ag/PA66 fabrics for personal thermal management via Joule heating with samples showing rapid heating response (up to 0.2 o C/sec) and long-term stability measured over 10,000 seconds. The needle-punched Ag/PA66 nonwoven fabrics, in spite of their low density of the order of 0.04g/cm 2 , exhibited high EMSE values of nearly 69-80dB, leading to excellent weight-normalised specific electromagnetic shielding effectiveness of over 1200 dB/(g/cm 3 ) in the 0.015-3GHz range. The production of Ag/PA66 needle punched nonwoven fabrics thus offers a facile route to develop multifunctional fabrics for EMI shielding as well as personal thermal management applications.

A Facile Approach for Preparing Ag Functionalized Nonwoven Polypropylene Membrane to Improve Its Electrical Conductivity and Electromagnetic Shielding Performance

“…M.S. Ozenet et al [6] reported that the shielding effect of nonwoven made of 6.7 dtex and 3.3 dtex conductive Ag/PA66 staple fibers was about 69–80 dB when the weight of nonwoven was only 0.04 g/cm 2 .…”

A new study on the influencing factors and mechanism of shielding effectiveness of woven fabrics containing stainless steel fibers

“…where t is the thickness of the shielding materials (mm), f is the incident wave frequency (MHz), is skin depth, and r and r are the conductivity and permeability relative to Cu, respectively. The increase of r and r due to increased SS fiber content in yarn resulted in better R and A values according to equations (2) and (3), which further led to the increase of SE values according to equation (1). That's why fabrics containing 30% SS fibers show the higher ability of EMSE than fabrics with 25% SS fibers content.…”

“…With the development of electronic industry, people's life is flooded with a large number of electromagnetic waves, which endangers human health and interferes with the operation of electronic equipment, thus leading to the increasing demand for radiation-proof functional textiles. Recent research papers on electromagnetic shielding effectiveness (EMSE) mainly focus on technology of electromagnetic shielding (EMS) materials [1][2][3][4][5], influencing factors [6][7][8][9][10][11][12], or calculation [12][13][14][15][16]. The blended metal fabric-EMS has so many advantages in price, technology maturity, EMS performance, and wear ability that it has become one of the most widely used EMS fabrics [7].…”

Enhanced Electromagnetic Interference Shielding in a Duplex-Phase Mg–9Li–3Al–1Zn Alloy Processed by Accumulative Roll Bonding

“…Electromagnetic radiation not only adversely affects human health and the environment, but also causes interference to electronic equipment and even causes major information losses. Therefore, electromagnetic shielding has received increasing attention, shielding materials play an important role in shielding effects, and the research on shielding materials becomes urgent [1][2][3].…”