scholarly journals Shielding Effectiveness and Sheet Conductance of Nonwoven Carbon-Fiber Sheets

2017 ◽  
Vol 59 (1) ◽  
pp. 84-92 ◽  
Author(s):  
John F. Dawson ◽  
Andrew N. Austin ◽  
Ian D. Flintoft ◽  
Andrew C. Marvin
2010 ◽  
Vol 168-170 ◽  
pp. 1021-1024
Author(s):  
Guo Xuan Xiong ◽  
Zhi Bin Zhang ◽  
Min Deng ◽  
Yu Fen Zhou

The cement-based composite shielding materials filled with carbon materials such as ordinary carbon materials (graphite, coke and carbon black), carbon fiber and nano-carbon materials (carbon nano-tube and nano-carbon black) were prepared. The relationship of conductivity and shielding effectiveness in a frequency range of 100 KHz~1.5 GHz was studied. The electric properties of cement-based composites filled with carbon fiber is better than other carbon materials. With the contents of carbon fiber of 5.vol%, the average shielding effectiveness is about 37 dB and the maximum shielding effectiveness reaches 40 dB.


Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1319 ◽  
Author(s):  
Ran Li ◽  
Huiping Lin ◽  
Piao Lan ◽  
Jie Gao ◽  
Yan Huang ◽  
...  

Lightweight electromagnetic interference shielding cellulose foam/carbon fiber composites were prepared by blending cellulose foam solution with carbon fibers and then freeze drying. Two kinds of carbon fiber (diameter of 7 μm) with different lengths were used, short carbon fibers (SCF, L/D = 100) and long carbon fibers (LCF, L/D = 300). It was observed that SCFs and LCFs built efficient network structures during the foaming process. Furthermore, the foaming process significantly increased the specific electromagnetic interference shielding effectiveness from 10 to 60 dB. In addition, cellulose/carbon fiber composite foams possessed good mechanical properties and low thermal conductivity of 0.021–0.046 W/(m·K).


2018 ◽  
Vol 37 (18) ◽  
pp. 1131-1141 ◽  
Author(s):  
Nisrin R Abdelal ◽  
Steven L Donaldson

In the current study, the production of multifunctional hybrid-stitched composites with improved interlaminar fracture toughness and electromagnetic interference shielding effectiveness is reported. Unidirectional carbon fiber-epoxy composite laminates stitched with Kevlar, nylon, hybrid stitched with both Kevlar and nylon and unstitched were prepared using resin infusion process. Representative specimens from unstitched and stitched composites were tested using rectangular waveguide and Mode I double cantilever beam tests. The Mode I experimental results showed that composite stitched with Kevlar exhibited the highest crack initiation interlaminar fracture toughness (GIC-initiation), whereas composite stitched with nylon exhibited the highest maximum crack propagation interlaminar fracture toughness (GIC-maximum). The four-hybrid stitching patterns exhibited higher GIC-initiation than the unstitched and stitched with nylon composites and lower than stitched with Kevlar composite, whereas they had higher GIC-maximum than the unstitched and stitched with Kevlar composites, although lower than stitched with nylon composite. The electromagnetic shielding effectiveness experimental results showed that stitched composites exhibited improved shielding effectiveness compared to unstitched composites. For example, composite stitched with nylon had highest shielding effectiveness value of 52.17 dB compared by the composite stitched with Kevlar which had 40.6 dB. The four hybrid-stitched composites exhibited similar shielding effectiveness with an average value of 32.75 dB compared to the unstitched composite shielding effectiveness of 22.84 dB. The experimental results comply with the initial goal of this study to manufacture multifunctional hybrid stitching composites with combined properties between Kevlar and nylon-stitched composites.


2003 ◽  
Vol 17 (08n09) ◽  
pp. 1235-1241 ◽  
Author(s):  
Ri Ichi Murakami ◽  
Hidetoshi Yamamoto ◽  
Chan Kong Kim ◽  
Cheol Mun Yim ◽  
Yun Hae Kim

The developments of electromagnetic wave shielding materials are strongly required because the malfunction of electronic equipment, mobile phone and wireless LAN avoids. In this study, it was investigated that the electromagnetic shielding effectiveness of carbon fiber sheets were enhanced by the ferrite which was coated by the microwave hydrothermal process. For coated carbon fiber sheet, the effects of ferrite and lamination of carbon fiber textile on the electromagnetic wave shielding effectiveness were discussed. In the range of frequency (100 – 1 GHz), the electromagnetic wave shielding effectiveness was measured by using TEM-Cell. The electromagnetic wave shielding effectiveness was greater for the coated carbon fiber sheets than for the uncoated carbon fiber sheets. When the insulation film was located between two carbon fiber sheets, the electromagnetic wave shielding effectiveness increased.


2014 ◽  
Vol 26 (7) ◽  
pp. 73203
Author(s):  
王富强 Wang Fuqiang ◽  
闫丽丽 Yan Lili ◽  
王东红 Wang Donghong ◽  
谷建宇 Gu Jianyu

2011 ◽  
Vol 45 (26) ◽  
pp. 2707-2715 ◽  
Author(s):  
Lai Chiu-Chun ◽  
Jen Chyi-Wen ◽  
Chang Yuh-Shyang ◽  
Huang Kuo-Shien

We considered polyamide 6 as a base material for a composite and added improved tourmaline and carbon fiber to manufacture a material that could release negative ions and resist electromagnetic waves. Through Fourier transform infrared spectroscopy and thermogravimetric analyses, we verified that the improved tourmaline could disperse homogeneously in the base material, whose thermal properties improved as the content of tourmaline increased. Scanning electron microscopy demonstrated that the added tourmaline and carbon fiber complemented the conductive network of the composite material. A negative ion detector and an infrared thermal imaging system both revealed that with an appropriate tourmaline content, the negative ion release properties of the composite material could reach 2020 units cm−3 with a difference in temperature of up to 7.54°C. Analyses by a four-point probe low-resistance tester and electromagnetic wave shielding effectiveness tester demonstrated that the osmotic concentration was approximately 4%, and the surface resistivity was high, up to 1.04 × 107 Ω cm−1, reaching the range of static dissipative materials (106–1012 Ω cm−1). The maximum electromagnetic wave shielding effectiveness was as high as 30 dB MHz−1.


2010 ◽  
Vol 437 ◽  
pp. 580-583
Author(s):  
Ho Chang ◽  
Yun Min Yeh ◽  
Ching Song Jwo ◽  
Sih Li Chen

This paper presents the development of a conductive composite film and the measurement of electromagnetic (EM) shielding effectiveness (SE) of the prepared film. A coaxial transmission-line technique based on ASTM D4935-99 Standard was used to measure the electromagnetic shielding effectiveness. A nickel nanofluid with an average particle size of 50 nm was prepared with a self-developed nanofluid synthesis system. By using a polymer blending method, carbon fiber and carbon fiber/nickel nanoparticles were blended with waterborne polyurethane (WPU) to prepare conductive composite films of 0.25 mm thick. Experimental results have shown that the electromagnetic shielding effectiveness value of the prepared conductive composite material can reach 26 dB within the range of 50 MHz ~ 1.5GHz.


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