scholarly journals ELECTRICAL CONDUCTIVITY AND ELECTROMAGNETIC SHIELDING EFFECTIVENESS OF SILICONE RUBBER FILLED WITH FERRITE AND GRAPHITE POWDERS

2011 ◽  
Vol 21 ◽  
pp. 93-104 ◽  
Author(s):  
Cristian Morari ◽  
Ionut Balan ◽  
Jana Pintea ◽  
Elena Chitanu ◽  
Iulian Iordache
Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1657 ◽  
Author(s):  
Marek Neruda ◽  
Lukas Vojtech

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.


2011 ◽  
Vol 675-677 ◽  
pp. 461-463
Author(s):  
Hai Ping Duan ◽  
Yu Ping Duan

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.


2020 ◽  
Vol 4 (1) ◽  
pp. 28
Author(s):  
Konstantinos Tserpes ◽  
Vasileios Tzatzadakis ◽  
Jens Bachmann

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.


2020 ◽  
Vol 12 (15) ◽  
pp. 5899
Author(s):  
Hung-Chuan Cheng ◽  
Chong-Rong Chen ◽  
Shan-hui Hsu ◽  
Kuo-Bing Cheng

The management of the electromagnetic interference (EMI) of thin, light, and inexpensive materials is important for consumer electronics and human health. This paper describes the development of conductive films that contain a silver (Ag) flake powder and multiwall carbon nanotube (MWCNT) hybrid grid on a polytetrafluoroethylene (PTFE) film for applications that require electromagnetic shielding (EMS) and a conductive film. The Ag and MWCNT hybrid grid was constructed with a wire diameter and spacing of 0.5 mm. The results indicated that the proposed conductive films with 0.4 wt% MWCNTs had higher electromagnetic shielding effectiveness (EMSE) and electrical conductivity than those with other MWCNT loading amounts. The results also showed that the film with 0.4 wt% MWCNT loading had a high 62.4 dB EMSE in the 1800 MHz frequency and 1.81 × 104 S/cm electrical conductivity. This combination improved stretchability, with 10% elongation at a 29% resistivity change rate. Conductive films with Ag/MWCNT electronic printing or lamination technologies could be used for EMI shielding and electrically conductive applications.


2019 ◽  
Vol 950 ◽  
pp. 97-102 ◽  
Author(s):  
Peng Zheng Liu ◽  
Ling Zhang ◽  
Wen Fei Wang ◽  
Wei Cheng ◽  
Deng Feng Li ◽  
...  

A two-step solvothermal method was employed to synthesize the Graphene/Fe3O4/BaTiO3(GFT). X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectra are used to observe the microstructure and magnetic properties of GFT, and the nanoparticles of Fe3O4and BaTiO3were uniformly deposited on the surface of the graphene nanosheets. Then GFT filler and the silicone rubber were mixed to manufacture the electromagnetic shielding materials. The vector network analyzer was employed to evaluate the electromagnetic shielding effectiveness of the modified electromagnetic shielding materials. The influence of the mole ratio of the GFT constituents, the mass content of the filler on the electromagnetic shielding effectiveness was studied between 1 GHz and 20 GHz. It is shown that the GFT/silicone rubber has the best electromagnetic shielding effectiveness for 24:1:1 of graphene: Fe3O4: BaTiO3and 16 % GFT.


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