Preparation of poly-p-phenylenebenzobisoxazole (PBO) fibrillated pulp and dielectric properties of carbon fiber/PBO wet-laid nonwoven fabric

2017 ◽  
Vol 88 (13) ◽  
pp. 1559-1568 ◽  
Author(s):  
Jingjing Bai ◽  
Hao Wang ◽  
Yi Wang ◽  
Jian Hu
Keyword(s):  
Dielectric Properties ◽  
Carbon Fiber ◽  
Mechanical Strength ◽  
Reflection Loss ◽  
Complex Permittivity ◽  
Nonwoven Fabric ◽  
Electromagnetic Properties ◽  
Optimum Thickness ◽  
Permittivity And Permeability ◽  
Different Content

A method to prepare a kind of wet-laid nonwoven fabric that can be used in microwave absorbing honeycomb is proposed. It was prepared through a papermaking process with carbon fiber (CF) and poly-p-phenylenebenzobisoxazole (PBO) fibrillated pulp. Fibrillated PBO pulp has a large surface area and lots of micro-fibrils which is beneficial for the uniformity and mechanical strength of the wet-laid nonwoven fabric. The electromagnetic properties and absorbing performances of the wet-laid nonwoven fabric with different content of CF were compared. The results showed that the complex permittivity increased when the content of the CF increased, and then decreased when the content was higher than 10 wt%. The resistivity measured by four probe testers decreased with the increase of the content of CF. Calculated by the measured complex permittivity and permeability, the CF/PBO wet-laid nonwoven fabric had a lowest reflection loss of -27.60 dB at a content of 20 wt%, with an optimum thickness of 1.72 mm.

Preparation, Characterization and Microwave Absorption Properties of Nano/Micro Carbon Fiber

2011 ◽  
Vol 306-307 ◽  
pp. 1712-1716 ◽  
Author(s):  
Xiao Ping Duan ◽  
Jun Hong Jin ◽  
Sheng Lin Yang ◽  
Guang Li
Keyword(s):  
Carbon Fiber ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Complex Permittivity ◽  
Small Diameter ◽  
Technical Condition ◽  
Drawing Ratio ◽  
Blend Fiber ◽  
Graphite Structure ◽  
Experimental Values

Carbon fiber with diameter in the range of nano to micro meter was prepared by carbonization of polyacrylonitrile (PAN) and polymethylmethacrylate (PMMA) blend fiber which was produced via wet spinning of PAN/PMMA blend solution. At the same technical condition, the high molecular of PAN favored the production of thin diameter of carbon fiber, and the high drawing ratio led to small diameter of the obtained nano/micro carbon fiber. The formation of graphite structure during carbonization was characterized by Raman and X-ray diffraction. The results improved that high temperature of carbonization developed high degree of graphitization and high conductivity of the nano/micro carbon fiber. The composites containing 2-8wt% of the obtained nano/micro carbon fiber were fabricated. The complex permittivity ε’ and ε’ for the composites in the frequency range of 8-12 GHz was measured, and the reflection loss for 180×180×3mm3 composites was also investigated. The microwave absorption property of these composites was improved greatly with increasing content of the nano/micro carbon fibers. At the addition of 8 wt% of the nano/micro carbon fiber, the reflection loss of the composite displayed -16dB at 11.3GHz, and the band with smaller than -5dB was 3GHz. Moreover, the calculated results based on the complex permittivity seem identical with the experimental values.

Electromagnetic Characteristics of Iron-Based Microwave Absorbing Materials

2011 ◽  
Vol 479 ◽  
pp. 106-111
Author(s):  
R.B. Yang ◽  
K.Y. Juan ◽  
Chien Yie Tsay ◽  
W.F. Liang ◽  
Chung Kwei Lin
Keyword(s):  
Complex Permittivity ◽  
Resonant Cavity ◽  
Electromagnetic Properties ◽  
Frequency Range ◽  
Microwave Absorbing Materials ◽  
Absorbing Materials ◽  
Permittivity And Permeability ◽  
Electromagnetic Characteristics ◽  
Iron Based ◽  
Microwave Absorbing

Nowadays human are exposed to an environment filling with electromagnetic waves over a wide frequency range. The electromagnetic properties of microwave absorbing materials plays an important role in the performance of civilian electromagnetic interference (EMI) shielding at low frequency range and military stealth technology at high frequency one. The electromagnetic properties include complex permittivity and permeability and its combination determines the electromagnetic wave absorption ability of a material. Complex permittivity and permeability can be measured by three different methods, i.e., free-space method, coaxial/waveguide method, and resonant cavity perturbation method. The first one requires a large space, expensive equipment, and not suitable for academic usage. In the present study, using coaxial/waveguide and resonant cavity perturbation methods, electromagnetic characteristics of iron-based microwave absorbing materials will be obtained and its microwave absorption performance will be investigated. In addition, a comparison between the measurements by these two methods will be addressed.

Electromagnetic Properties of Nanometer SiC/CNTs Composite

2009 ◽  
Vol 79-82 ◽  
pp. 349-352 ◽  
Author(s):  
Jian Xun Yao ◽  
Liu Ying Wang ◽  
Gu Liu ◽  
Shao Chun Hua
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Complex Permittivity ◽  
Mass Fraction ◽  
Low Frequency ◽  
Electromagnetic Properties ◽  
Transmission Line Theory ◽  
Microwave Absorption Properties ◽  
Line Theory ◽  
Maximum Reflection Loss

Both the complex permittivity and permeability of nanometer SiC and nanometer SiC/CNTs composite were investigated by Hewlett-Packard 8510B Network Analyzer. The results show that the complex permittivity of nanometer SiC/CNTs composite is much higher than that of nanometer SiC. Reflection curves of nanometer SiC and nanometer SiC/CNTs composite calculated with electromagnetic wave transmission-line theory show that the addition of CNTs at 6 wt%, 12 wt% and 18 wt% in nanometer SiC absorber can improve its microwave absorption properties strongly. There is a relationship between the mass fraction of CNTs and microwave absorption ability. With increase of the mass fraction of CNTs, its microwave absorption ability firstly increased then decreased. From the simulation, it was found that nanometer SiC with 12 wt% CNTs gave the optimum microwave absorption. The corresponding frequency of maximum reflection loss value of nanometer SiC/CNTs composite gradually moves to the low frequency range with increase of thickness. The maximum reflection loss value of nanometer SiC/CNTs composite (CNTs content is 12 wt%) was -25.74dB at the corresponding frequency of 11.60 GHz with a bandwidth under -5 dB (68% absorption) is 7.16 GHz when the thickness is 2.0 mm.

The influence of carbon fiber diameter and content on the dielectric properties of wet-laid nonwoven fabric

2018 ◽  
Vol 89 (13) ◽  
pp. 2542-2552 ◽  
Author(s):  
Hao Wang ◽  
Jin Long ◽  
Yi Wang ◽  
Yun Liang ◽  
Jian Hu ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Carbon Fiber ◽  
Fiber Diameter ◽  
Nonwoven Fabric

Effect of the cobalt ferrite and carbon fiber powder doping ratio on the electromagnetic properties of coated polyaniline-based polyester–cotton fabric

2021 ◽  
pp. 004051752110608
Author(s):  
Yi Wang ◽  
Yuanjun Liu ◽  
Chao Yang ◽  
Xiaoming Zhao
Keyword(s):  
Dielectric Constant ◽  
Carbon Fiber ◽  
Cotton Fabric ◽  
Imaginary Part ◽  
Reflection Loss ◽  
Cobalt Ferrite ◽  
Electromagnetic Properties ◽  
Loss Angle ◽  
The Real ◽  
Doping Ratio

In this project, firstly, polyaniline-based polyester–cotton fabric was prepared by in situ polymerization using polyester–cotton fabric as the base fabric, aniline as the monomer, ammonium persulfate as the oxidizer, and camphor sulfonic acid as the dopant. Secondly, cobalt ferrite/carbon fiber powder-coated polyaniline-based polyester–cotton fabric was prepared by the textile coating process using polyaniline-based polyester–cotton fabric as the base fabric, PU2540-type polyurethane as the adhesive, and cobalt ferrite and carbon fiber powder as functional particles. Finally, the effect of the cobalt ferrite and carbon fiber powder doping ratio on the shielding effectiveness, reflection loss, dielectric constant real part, imaginary part, and loss angle tangent of cobalt ferrite/carbon fiber powder-coated polyaniline-based polyester–cotton fabric was studied by using the controlled variable method with emphasis on the cobalt ferrite/carbon fiber powder doping ratio. The results show that in the frequency range of 0.01–3.0 GHz, when the doping ratio of cobalt ferrite to carbon fiber powder is 0:3, the reflection loss of cobalt ferrite/carbon fiber powder-coated polyaniline-based polyester–cotton fabric reaches the minimum value at 1.49 GHz, the minimum reflection loss is –21.4 dB, and the effective absorption band is 1.25–1.94 GHz. In the test band, the shielding efficiency, reflection loss, the real part and imaginary part of the dielectric constant, and the loss angle tangent of the carbon fiber powder-coated polyaniline-based polyester–cotton fabric are larger than those of cobalt ferrite-coated polyaniline-based polyester–cotton fabric. The smaller the doping ratio of cobalt ferrite to carbon fiber powder, the larger value of the shielding efficiency, reflection loss, the real part and imaginary part of the dielectric constant, and loss angle tangent of the cobalt ferrite/carbon fiber powder-coated polyaniline-based polyester–cotton fabric.

Direct growth of thermally reduced graphene oxide on carbon fiber for enhanced mechanical strength

2020 ◽  
Vol 193 ◽  
pp. 108010
Author(s):  
Beom-Gon Cho ◽  
Shalik Ram Joshi ◽  
Jaekyo Lee ◽  
Young-Bin Park ◽  
Gun-Ho Kim
Keyword(s):  
Graphene Oxide ◽  
Carbon Fiber ◽  
Mechanical Strength ◽  
Reduced Graphene Oxide ◽  
Reduced Graphene ◽  
Direct Growth

scholarly journals Improving flexural and dielectric properties of carbon fiber epoxy composite laminates reinforced with carbon nanotubes interlayer using electrospray deposition

2020 ◽  
Vol 9 (1) ◽  
pp. 1170-1182
Author(s):  
Muhammad Razlan Zakaria ◽  
Hazizan Md Akil ◽  
Mohd Firdaus Omar ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Aslina Anjang Ab Rahman ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Dielectric Properties ◽  
Carbon Fiber ◽  
Composite Laminates ◽  
Epoxy Composite ◽  
Flexural Modulus ◽  
X Ray Diffraction ◽  
Electrospray Deposition ◽  
Ft Ir ◽  
Carbon Fiber Epoxy

AbstractThe electrospray deposition method was used to deposit carbon nanotubes (CNT) onto the surfaces of woven carbon fiber (CF) to produce woven hybrid carbon fiber–carbon nanotubes (CF–CNT). Extreme high-resolution field emission scanning electron microscopy (XHR-FESEM), X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the woven hybrid CF–CNT. The results demonstrated that CNT was successfully and homogenously distributed on the woven CF surface. Woven hybrid CF–CNT epoxy composite laminates were then prepared and compared with woven CF epoxy composite laminates in terms of their flexural and dielectric properties. The results indicated that the flexural strength, flexural modulus and dielectric constant of the woven hybrid CF–CNT epoxy composite laminates were improved up to 19, 27 and 25%, respectively, compared with the woven CF epoxy composite laminates.

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