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

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 296 ◽  
Author(s):  
Dongfeng Shao ◽  
Hongwei Zhang ◽  
Lizhen Tao ◽  
Kan Cao ◽  
Qufu Wei
Keyword(s):  
Electrical Conductivity ◽  
Silver Ions ◽  
Reduction Reaction ◽  
Electromagnetic Shielding ◽  
Shielding Effect ◽  
Shielding Effectiveness ◽  
Special Equipment ◽  
Preparation Methods ◽  
Polypropylene Membrane ◽  
Washing Durability

The commonly used preparation methods of polypropylene functionalization require special equipment to be put into use or take a long time, which limits its application. Therefore, a simple and economical method for preparing silver functionalized nonwoven polypropylene membrane was studied herein. Triethanolamine was first coated on the surface of the polypropylene, and then Ag was deposited on the surface of polypropylene using a continuous reduction reaction of triethanolamine and silver ions. Surface morphology, crystal structure, and surface chemistry during the preparation of Ag functionalized nonwoven polypropylene were investigated. The electrical conductivity, electromagnetic shielding properties, and washing durability of the treated nonwoven polypropylene were also studied. It was found that Ag was uniformly deposited on the surface of the nonwoven polypropylene, and the coating reaction did not change the chemical structure of the polypropylene. The crystallinity and thermal stability of polypropylene were improved after silver coated polypropylene. The washing experiment results showed that the weight gain rate of the treated nonwoven relative to the untreated sample after the 90 min washing ranged from 6.72% to 9.64%. The resistance test results showed that the maximum surface resistivity of Ag coated nonwoven polypropylene was about 1.95 × 105 Ω, which was 64,615 times lower than the original. In addition, the results showed that the maximum electromagnetic shielding effectiveness of the Ag coated nonwoven polypropylene was about 71.6 dB, showing a very good electromagnetic shielding effect.

scholarly journals Electromagnetic Shielding Effectiveness of Woven Fabrics with High Electrical Conductivity: Complete Derivation and Verification of Analytical Model

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1657 ◽  
Author(s):  
Marek Neruda ◽  
Lukas Vojtech
Keyword(s):  
Electrical Conductivity ◽  
Analytical Model ◽  
Electromagnetic Interference ◽  
Woven Fabrics ◽  
Electromagnetic Shielding ◽  
High Electrical Conductivity ◽  
Shielding Effectiveness ◽  
Textile Composite ◽  
A Value ◽  
Electromagnetic Shielding Effectiveness

In this paper, electromagnetic shielding effectiveness of woven fabrics with high electrical conductivity is investigated. Electromagnetic interference-shielding woven-textile composite materials were developed from a highly electrically conductive blend of polyester and the coated yarns of Au on a polyamide base. A complete analytical model of the electromagnetic shielding effectiveness of the materials with apertures is derived in detail, including foil, material with one aperture, and material with multiple apertures (fabrics). The derived analytical model is compared for fabrics with measurement of real samples. The key finding of the research is that the presented analytical model expands the shielding theory and is valid for woven fabrics manufactured from mixed and coated yarns with a value of electrical conductivity equal to and/or higher than σ = 244 S/m and an excellent electromagnetic shielding effectiveness value of 25–50 dB at 0.03–1.5 GHz, which makes it a promising candidate for application in electromagnetic interference (EMI) shielding.

Electrical Conductivity and Electromagnetic Shielding Effectiveness of CB/ABS Composites

2011 ◽  
Vol 675-677 ◽  
pp. 461-463
Author(s):  
Hai Ping Duan ◽  
Yu Ping Duan
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Mass Fraction ◽  
Acrylonitrile Butadiene Styrene ◽  
Volume Resistivity ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Percolation Effect ◽  
Electromagnetic Shielding Effectiveness ◽  
Butadiene Styrene

In this paper, the effects of carbon black (CB) mass fraction on volume resistivity and electromagnetic shielding effectiveness (SE) of CB/Acrylonitrile Butadiene Styrene (ABS) composites were studied. The results indicated that when CB mass fraction was over 15 wt%, the volume resistivity dropped sharply and when it rose to 35 wt%, the volume resistivity achieved the lowest value about 103Ω·cm. In addition, there are two obvious percolation effect at 15~20 wt% and 25~35 wt% CB respectively in the course of the volume resistivity changing. Titanate coupling agent could greatly improve conduction and SE of CB/ABS composites. Lastly, the SE of CB/ABS composites was investigated by experimental observation.

The Preparation of Ni-Co-Fe/PU Magnetic Composite Membrane

2011 ◽  
Vol 239-242 ◽  
pp. 2937-2941
Author(s):  
Jian Chao Zhan
Keyword(s):  
Adverse Effect ◽  
Electrical Conductivity ◽  
Water Vapor Permeability ◽  
Electromagnetic Shielding ◽  
Vapor Permeability ◽  
Magnetic Composite ◽  
Shielding Effectiveness ◽  
Wear Performance ◽  
Conductivity Water ◽  
Polyamide Fabric

On the base of electroless plating on fabric, the Ni-Co-Fe was plated on the PU membrane of coated polyamide fabric and the respiratory electromagnetic shielding fabric was developed. The functionality and wear-ability of electromagnetic shielding fabric was tested and analyzed. The results showed that it has good electrical conductivity, water vapor permeability, electromagnetic shielding performance and durability and so on. With the weight increasing rate goes up, the shielding effectiveness, vapor permeability and electrical conductivity increases obviously, then prone to slow increment. The plated layer on fabric has an adverse effect on the wear performance and on the premise of meeting respiratory and electromagnetic shielding performance, the thickness of plated layer should be decreased to the least extend.

scholarly journals Electrical Conductivity and Electromagnetic Shielding Effectiveness of Bio-Composites

2020 ◽  
Vol 4 (1) ◽  
pp. 28
Author(s):  
Konstantinos Tserpes ◽  
Vasileios Tzatzadakis ◽  
Jens Bachmann
Keyword(s):  
Electrical Conductivity ◽  
Carbon Fiber ◽  
Epoxy Resin ◽  
Numerical Models ◽  
Experimental Testing ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Carbon Fiber Fabric ◽  
Electromagnetic Shielding Effectiveness ◽  
Fiber Fabric

In this paper, the electrical conductivity and electromagnetic shielding effectiveness of two bio-composites are studied by experimental testing and numerical models. Two monolithic composites with partly bio-based content were manufactured. The first bio-composite is made of a carbon fiber fabric prepreg and a partly bio-based (rosin) epoxy resin (CF/Rosin). The second bio-composite is a combination of prepregs of carbon fiber fabric/epoxy resin and flax fiber fabric/epoxy resin (CF-Flax/Epoxy). A single line infusion process was used prior to the curing step in the autoclave. Both variants are exemplary for the possibility of introducing bio-based materials in high performance CFRP. In-plane and out-of-plane electrical conductivity tests were conducted according to Airbus standards AITM2 0064 and AITM2 0065, respectively. Electromagnetic shielding effectiveness tests were conducted based on the standard ASTM D 4935-10. Materials were prepared at the German Aerospace Center (DLR), while characterization tests were conducted at the University of Patras. In addition to the tests, numerical models of representative volume elements were developed, using the DIGIMAT software, to predict the electrical conductivity of the two bio-composites. The preliminary numerical results show a good agreement with the experimental results.

Research on Shielding Effectiveness Calculation Method of Electromagnetic Shielding Materials

2020 ◽  
Vol 304 ◽  
pp. 137-141
Author(s):  
Nan Mei ◽  
Xiao Yu Wang ◽  
Xin Wang ◽  
Hua Fang Li ◽  
Min Hong Wei ◽  
...  
Keyword(s):  
Calculation Method ◽  
Electromagnetic Shielding ◽  
Shielding Effect ◽  
Network Analyzer ◽  
Shielding Effectiveness ◽  
Transmission Line Theory ◽  
Acceptable Accuracy ◽  
Important Index ◽  
Line Theory ◽  
Reflection Theory

Electromagnetic shielding materials are widely used in engineering. Shielding effectiveness is an important index to measure the shielding effect of electromagnetic shielding materials. A method for calculating the shielding effectiveness of electromagnetic shielding materials is discussed in this paper. This method applies the small reflection theory in transmission line theory. Two kinds of materials are selected as samples. Firstly, the shielding performance is calculated by calculation. Then, shielding performance was measured using a network analyzer and coaxial devices. By comparing the above two results, the feasibility of this method is verified. By using this method, the shielding performance with acceptable accuracy can be obtained when the electromagnetic parameters of the material are known. Thus, the limitation for the application of electromagnetic shielding materials is reduced.

Design and Shielding Effectiveness of Electromagnetic Shielding Textiles

2013 ◽  
Vol 796 ◽  
pp. 653-656
Author(s):  
Yan Su Liu ◽  
Guo Hua Chen
Keyword(s):  
Influence Factor ◽  
Electromagnetic Shielding ◽  
Shielding Effect ◽  
Tunnel Effect ◽  
Shield Effectiveness ◽  
Shielding Effectiveness ◽  
Exposed Area ◽  
Slit Size ◽  
Radiation Material ◽  
Garment Design

.In order to design better anti-radiation and electromagnetic shielding fabric and the clothing and makes it maintained better of electromagnetic shield effectiveness, the influence of radiation source, radiation distance, anti-electromagnetic radiation material, fabric structure, gap size, holes area, clothing exposed area as well as the tunnel effect and so on the fabric radiation protection performance were comprehensively discussed in this article. As well, according to these influence factor analysis the regular conditions that the electromagnetic shielding fabric and garment design should be meet. The analysis result indicated that the shielding effectiveness of the fabric was decreased with the increase of the radiant frequency, the fabric slit size, the hole area and enhanced with the growing of the metal content, the organizational structure close degree as well as the radiation distance.In the case of the equal shielding effect, the bigger exposed area leads weaker electromagnetic shielding effectiveness and if the exposed area oversize can cause the shield effect vanished. Also the clothing shield potency was related to the opening radius, the length, the inside and outside dielectric constant, the permeability of the shirt or cuff. The comprehensive effectiveness of electromagnetic shielding fabrics will be gradually improved if they can meet these regular conditions continually.

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