Mechanical performance and electromagnetic shielding effectiveness of composites based on Ag-plating cellulose micro-nano fibers and epoxy

2017 ◽  
Vol 37 (8) ◽  
pp. 805-813 ◽  
Author(s):  
Yu Wang ◽  
Jin Tian Huang
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Interference ◽  
Mechanical Performance ◽  
Oxide Phase ◽  
Cellulose Fibers ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Emi Shielding Effectiveness ◽  
Nano Cellulose ◽  
Electromagnetic Shielding Effectiveness

Abstract Mechanical and electromagnetic interference shielding composites containing Ag-plating micro-nano cellulose fibers (ANCFs) were prepared as multifunctional materials. ANCFs, as electromagnetic wave reflection filler containing micro-nano cellulose fibers (NCFs) used as the structural component to reinforce the mechanical strength and Ag enhancing electromagnetic shielding effectiveness, were prepared by electroless Ag-plating technology on NCFs surfaces. Ag coating had a thickness of 60 µm without the oxide phase detected. The incorporation of 5 wt % ANCFs into epoxy (EP) substrate yielded impact strength and flexural strength of 1.84 kJ/m2 and 41.6 MPa, which is approximately 2.4 times and 1.41 times higher than EP. The ANCFs-EP composite performed an electromagnetic shielding effectiveness of 34–25 dB at a frequency of 90 kHz in the electromagnetic wave; the EMI shielding effectiveness was improved obviously up to 34 dB, which can meet the requirement of general places.

scholarly journals Ultrathin Multilayer Textile Structure with Enhanced EMI Shielding and Air-Permeable Properties

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4176
Author(s):  
Shi Hu ◽  
Dan Wang ◽  
Aravin Prince Periyasamy ◽  
Dana Kremenakova ◽  
Jiri Militky ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Single Layer ◽  
Electromagnetic Shielding ◽  
Shielding Effect ◽  
Material Surface ◽  
Test Results ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Emi Shielding Effectiveness ◽  
Electromagnetic Shielding Effectiveness

A textile material’s electromagnetic interference (EMI) shielding effectiveness mainly depends on the material’s electrical conductivity and porosity. Enhancing the conductivity of the material surface can effectively improve the electromagnetic shielding effectiveness. However, the use of highly conductive materials increases production cost, and limits the enhancement of electromagnetic shielding effectiveness. This work aims to improve the EMI shielding effectiveness (EMSE) by using an ultrathin multilayer structure and the air-permeable textile MEFTEX. MEFTEX is a copper-coated non-woven ultrathin fabric. The single-layer MEFTEX SE test results show that the higher its mass per unit area (MEFTEX 30), the better its SE property between 56.14 dB and 62.53 dB in the frequency band 30 MHz–1.5 GHz. Through comparative testing of three groups samples, a higher electromagnetic shielding effect is obtained via multilayer structures due to the increase in thickness and decrease of volume electrical resistivity. Compared to a single layer, the EMI shielding effectiveness of five layers of MEFTEX increases by 44.27–83.8%. Due to its ultrathin and porous structure, and considering the balance from porosity and SE, MEFTEX 10 with three to four layers can still maintain air permeability from 2942 L/m2/s–3658 L/m2/s.

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.

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

2019 ◽  
Vol 50 (6) ◽  
pp. 830-846
Author(s):  
Yalan Yang ◽  
Jianping Wang ◽  
Zhe Liu ◽  
Zhujun Wang
Keyword(s):  
Stainless Steel ◽  
Electromagnetic Wave ◽  
Electromagnetic Radiation ◽  
Woven Fabrics ◽  
Electromagnetic Shielding ◽  
Living Environment ◽  
Steel Fibers ◽  
Wave Frequency ◽  
Shielding Effectiveness ◽  
Electromagnetic Shielding Effectiveness

Electromagnetic radiation is becoming increasingly serious around our living environment, which seriously endangers people's health and interferes with the operation of electronic equipment. The research and development of anti-electromagnetic radiation fabric have drawn more and more attention. However, the influencing rules and mechanisms of conductive fiber content, fabric tightness, warp–weft density, conductive yarn arrangement, weave type, and electromagnetic wave frequency on fabric electromagnetic shielding effectiveness have not been clarified. Therefore, in this study, a series of fabrics containing stainless steel fibers were produced. Meanwhile, the influencing rules of various factors on electromagnetic shielding effectiveness and the quantitative relationship between some factors and electromagnetic shielding effectiveness were discussed. The results showed that all factors had different degrees of influence on electromagnetic shielding effectiveness, and the relationship between electromagnetic shielding effectiveness and electromagnetic wave frequency could be approximately expressed as: [Formula: see text]. At the same time, the influencing mechanisms of various factors on electromagnetic shielding effectiveness were analyzed in combination with fabric microstructure and macrostructure, the intrinsic parameters of the fabric and the electromagnetic shielding effectiveness mechanism. The results are expected to provide a reference for the establishment of electromagnetic shielding fabric model and enterprise production.

Study to Wood Electromagnetic Shielding Composites Laminated with Aluminum Plates

2011 ◽  
Vol 280 ◽  
pp. 159-164 ◽  
Author(s):  
Ke Yang Lu ◽  
Feng Fu ◽  
Yue Jin Fu ◽  
Zhi Yong Cai
Keyword(s):  
Electromagnetic Interference ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Building Product ◽  
Static Modulus ◽  
Electrical Devices ◽  
Aluminum Plates ◽  
Static Modulus Of Elasticity ◽  
Electromagnetic Shielding Effectiveness ◽  
Shielding Composites

Radiations from different electrical devices cause electromagnetic interference which will influence the performance realization of other electromagnetic device and cause the health concerns. The aluminum plates were then used to develop wood electromagnetic shielding composites by laminating with the plywood. Their static modulus of elasticity and electromagnetic shielding effectiveness of the composites with different thickness and position of aluminum plates were evaluated. The results showed that the strength of composites were improved by laminating the aluminum plates on the surface. The electromagnetic shielding performance of the composites were increased by the design of the multilayer and sandwich shielding structure. Again, It was also found that the composites made by laminating two aluminum plates (1mm, in the middle or on the surface) had a better shielding effectiveness (60 dB to 92 dB, 60 dB to 106 dB, Ranged from 1 GHz to 10 GHz) and met the requirement for a commercial electromagnetic shielding building product.

The Influence of Fabric Structures of the Woven Fabrics on Electromagnetic Shielding Effectiveness

2011 ◽  
Vol 239-242 ◽  
pp. 1994-1997 ◽  
Author(s):  
Ching Wen Lou ◽  
Yi Chang Yang ◽  
Chin Mei Lin ◽  
Ching Wen Lin ◽  
Lin Chao Chen ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Electromagnetic Interference ◽  
Woven Fabrics ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Frequency Range ◽  
Fabric Structures ◽  
Electromagnetic Shielding Effectiveness

Stainless steel (SS) blended yarns with electromagnetic interference (EMI) were made into woven fabrics, after which the fabrics were evaluated with electromagnetic shielding effectiveness (EMSE). Parameters of laminated angle and the lamination number layers affected the fabrics’ EMSE differently. In addition, density of unidirectional SS yarns affected EMSE in frequency range of 200 to 500 MHz , so as the density of cross SS yarns on a frequency over 1000 MHz.

scholarly journals Multilayer-Structured Wood Electroless Cu–Ni Composite Coatings for Electromagnetic Interference Shielding

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 740
Author(s):  
Yanfei Pan ◽  
Dingwen Yin ◽  
Xiaofang Yu ◽  
Nanyi Hao ◽  
Jintian Huang
Keyword(s):  
Surface Roughness ◽  
Surface Morphology ◽  
Electromagnetic Interference ◽  
Composite Coatings ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Frequency Range ◽  
Electromagnetic Interference Shielding ◽  
Electromagnetic Shielding Effectiveness ◽  
The Ideal

The lightweight multilayer-structured electromagnetic interference shielding composite coatings with controllable electromagnetic gradient on wood surface were prepared via a simple multiple electroless copper–nickel (Cu–Ni) approach. The surface morphology, conductivity, hydrophobicity property and electromagnetic shielding effectiveness of the composite coatings were investigated. The surface roughness and conductivity of the composite coatings were enhanced with the increase in the number of depositions. The surface morphology demonstrated that the roughness was decreased with the process of multiple electroless. The coatings were compact and homogeneous as the deposition run was three. Here, the Sa (Sa illustrated Surface Roughness) value of coatings was 4.497 μm. The ideal conductivity of composite coatings can be obtained as the number of depositions was four. Electromagnetic shielding effectiveness reached average 90.69 dB in the frequency range from 300 kHz to 2.0 GHz. This study provides a new pathway for fabricating lightweight multilayer-structured electromagnetic interference shielding with controllable electromagnetic gradient and hydrophobic composite coatings-based wood.

The Process and Property Characteristic of Electromagnetic Shielding Functional Warp Knitted Composite Fabrics

2011 ◽  
Vol 287-290 ◽  
pp. 712-716 ◽  
Author(s):  
Jia Hornag Lin ◽  
Yu Tien Huang ◽  
Chin Mei Lin ◽  
Yi Chang Yang ◽  
Ching Wen Lou
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Electromagnetic Wave ◽  
Life Quality ◽  
Strength Test ◽  
Electromagnetic Shielding ◽  
Bamboo Charcoal ◽  
Shielding Effectiveness ◽  
Knitted Fabrics ◽  
Electromagnetic Shielding Effectiveness

The scientific progress has improved human life quality, meanwhile today's high-stress lifestyle has resulted in a rising demand for health care and well-being products. The high technology products and innovation make our life more convenient and at the same time the negative effects, such as electrostatic and electromagnetic wave. High electromagnetic wave affects the human body in different ways. Technological innovation and product aesthetics are both important for modern life quality. Companies have invested in research, development and essential household items to improve the lives such as thermal retentivity and antistatic. In this study, PET fiber was used as warp, and PET fiber, bamboo charcoal nylon fiber and stainless steel fiber employed as weft to weave three groups of resilient warp knitted fabrics. Then various examination have been conducted, including electromagnetic shielding effectiveness, tensile strength test, tearing strength test, burst strength test. The results indicate that the electromagnetic shielding effectiveness of bamboo charcoal / stainless steel resilient warp knitted fabrics attained 35 dB and the shielding achieved 99.9 %. The tensile strength of bamboo charcoal / stainless steel resilient warp knitted fabrics (weft) reached 26 MPa.

Electromagnetic Shielding of Multi-Walled Carbon Nanotube/Epoxy Nanocomposites

2008 ◽  
Vol 47-50 ◽  
pp. 475-478 ◽  
Author(s):  
Meng Kao Yeh ◽  
Nyan Hwa Tai ◽  
Guo Chian Ling ◽  
Chi Yuan Huang
Keyword(s):  
Carbon Nanotubes ◽  
Electromagnetic Interference ◽  
Chemical Vapor ◽  
Electromagnetic Shielding ◽  
Tensile Failure ◽  
Chemical Vapor Deposition Method ◽  
Shielding Effectiveness ◽  
Spreading Process ◽  
Weight Percentage ◽  
Electromagnetic Shielding Effectiveness

In this paper, carbon nanotubes were used as the reinforcements in the polymer composites for the application of electromagnetic interference, due to their outstanding mechanical and electrical properties. The multi-walled carbon nanotubes (MWNTs) synthesized by the chemical vapor deposition method were used to reinforce the epoxy resin by both mixing and spreading processes. The effects of the weight percentage and the reinforced form of MWNTs on electromagnetic interference shielding effectiveness, including the absorbance and the reflectance, were investigated. From experimental results, the electromagnetic shielding effectiveness of the nanocomposite specimens is improved with increasing content of MWNTs. The nanocomposites fabricated by the spreading process have better shielding effectiveness than those made by the mixing process. The nanocomposites, made by the spreading process with 2 wt% MWNTs, had up to 22.69 dB of electromagnetic shielding effectiveness. The reflectance percentage of electromagnetic shielding increases for higher content of MWNTs. The layerwise form of MWNTs in the nanocomposites, resulting from the spreading process and having a better electromagnetic shielding effectiveness, can be observed from the morphologies of the tensile failure surfaces of the nanocomposite specimens by filed emission scanning electron microscopy.

Preparation and properties of graphene aerogel/cotton composite flexible fabric with electromagnetic interference (EMI) shielding function

2021 ◽  
pp. 152808372198927
Author(s):  
Peng Wang ◽  
Shuqiang Liu ◽  
Man Zhang ◽  
Gaihong Wu ◽  
Kaiwen Wang ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Waterborne Polyurethane ◽  
Development Trend ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Graphene Aerogel ◽  
Emi Shielding Effectiveness ◽  
Aerogel Composite ◽  
Electromagnetic Pollution

In order to alleviate the problems caused by electromagnetic pollution and simultaneously adapt to the future development trend of flexible wearable electronic equipment, it is high time to focus on the research of light weight, flexible and efficient electromagnetic interference (EMI) shielding material. A graphene aerogel composite EMI shielding composite fabric was prepared by combining graphene aerogel with fabric through the connection of waterborne polyurethane. The influence of aerogel amount on the EMI shielding function of fabric was discussed, and the waterborne polyurethane dosage on fabric mechanics and fabric style was also investigated. The result shows the composite fabric EMI shielding effectiveness reached 28 dB when the graphene aerogel amount was 25 mL (only 0.066 mL/cm2), which has satisfied the civilian requirements (20 dB). A good adhesion fastness between graphene and cotton fabric was obtained and the mechanical strength was also improved when the content of waterborne polyurethane was 20 mL. Graphene aerogel electromagnetic shielding composite fabric with good electromagnetic shielding performance and less consumption of nano carbon materials will have a good industrial application prospect.

scholarly journals Analysis of the effect of different absorber materials and loading on the shielding effectiveness of a metallic enclosure

2015 ◽  
Vol 13 ◽  
pp. 155-159 ◽  
Author(s):  
S. Parr ◽  
H. Karcoon ◽  
S. Dickmann ◽  
R. Rambousky
Keyword(s):  
Complex System ◽  
Electromagnetic Interference ◽  
Electromagnetic Shielding ◽  
Electronic Equipment ◽  
Shielding Effectiveness ◽  
Resonant Frequencies ◽  
Parameter Variations ◽  
Electromagnetic Shielding Effectiveness ◽  
Dielectric Structures

Abstract. Metallic rooms as part of a complex system, like a ship, are necessarily connected electromagnetically via apertures and cables to the outside. Therefore, their electromagnetic shielding effectiveness (SE) is limited by ventilation openings, cable feed-throughs and door gaps. Thus, electronic equipment inside these rooms is susceptible to outer electromagnetic threats like IEM (Intentional Electromagnetic Interference). Dielectric or magnetic absorber inside such a screened room can be used in order to prevent the SE from collapsing at the resonant frequencies. In this contribution, the effect of different available absorber materials is compared, as well as other properties like weight and workability. Furthermore, parameter variations of the absorber as well as the effect of loading in form of metallic and dielectric structures on the SE are analyzed.

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