Preparation of single-layer coating polyester cotton composites with electric loss of their electromagnetic properties

Abstract

In this paper, single-layer coated polyester–cotton composites were prepared using PU-2540 waterborne polyurethane resin as the adhesive, graphite and silicon carbide as functional particles, and adopting a coating technology on the plain polyester–cotton fabric. First, the single-layer graphite-coated polyester cotton composite was prepared with graphite as the functional particle, and the influence of graphite content on the reflection loss and shielding effectiveness was studied. When the applied electric field frequency is 1610 MHz and the graphite content is 40 wt%, the minimum reflection loss is −26 dB; when the applied electric field frequency is 39.9 MHz and the graphite content is 50 wt%, the maximum shielding effectiveness is 12 dB. Then the single-layer silicon carbide-coated polyester–cotton composite was prepared with silicon carbide as the functional particle, and the influence of silicon carbide content on the reflection loss and shielding effectiveness was studied. With the applied electric field in the range 500∼3000 MHz, the greater the content of silicon carbide, the smaller the reflection loss, the better the wave-absorbing ability, the larger the shielding effectiveness, and the better the shielding performance. Finally, the single-layer graphite/silicon carbide-coated polyester–cotton composites were prepared by doping graphite and silicon carbide in different proportions, and the influence of doping ratio on dielectric properties, reflection loss, and shielding effectiveness was investigated. The real part of the dielectric constant of the material was highest – that is, the polarization ability of the material was best when there were only graphite particles in the doping medium and the silicon carbide content was 0. The imaginary part of the dielectric constant and the tangent of loss angle of the material were the highest – that is, the loss and attenuation ability of the material were best – when the doping ratio of graphite to silicon carbide is 4:1. With the applied electric field in the range 500∼3000 MHz, and with increasing graphite content, the reflection loss of the material became smaller, showing an enhanced wave-absorbing property, and the shielding effectiveness of the material increased, showing an enhanced shielding performance.

Preparation and characterization of an electromagnetic composite polypyrrole/polyethylene short filament geotextile

“…After the setup was completed, we tested the shielding performance and RL of the polypyrrole/PE short filament geotextile composite. 29…”

“…After the setup was completed, we tested the shielding performance and RL of the polypyrrole/PE short filament geotextile composite. 29 The RL is the energy loss between the incident wave and the reflected wave at the absorbing material-air interface, and its unit is dB, which indicates that the ratio of the reflected wave power to the incident wave power after the electromagnetic microwave is incident on the material surface, and can be usually expressed as RL ¼ 10lg(Pa/Pm), where Pa represents the reflected wave power and Pm represents the incident wave power. Generally, when the RL value of the material is not greater than -10 dB, it can be considered that 90% of the electromagnetic waves are lost.…”

Study on Electromagnetic Properties of Graphite/Graphene/Silver-Coated Copper Powder Monolayer Coated Composites

“…Coating is easily applicable to most of the current materials that are worth studying from a cost, processing and performance aspect, and it easy to service at a later period [1][2][3]. According to the absorbing and shielding mechanism of the coating, the properties mainly depend on the functional particles, layer number and layer thickness of the electromagnetic protection materials [4][5][6].…”