Binary synergistic enhancement of dielectric and microwave absorption properties: A composite of arm symmetrical PbS dendrites and polyvinylidene fluoride

Pan, Yafei; Wang, Guang-Sheng; Liu, Lei; Guo, Lin; Yu, Shu‐Hong

doi:10.1007/s12274-016-1290-8

Cited by 167 publications

(65 citation statements)

References 50 publications

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“…Noticeably, the defects of the g‐C 3 N 4 2D structures can also bear the observed magnetic resonance . The percolation theory indicates that in the improved impedance matching situation, the input waves more percolate inside the absorbing medium and then be attenuated, given by

Z = \frac{Z_{in}}{Z_{0}} = \sqrt{\frac{μ_{r}}{ε_{r}}}

equation . Based on the results, significant impedance matching of the g‐C 3 N 4 /PMMA nanocomposite implies for its substantial microwave absorption properties.…”

Section: Resultsmentioning

confidence: 93%

Novel, promising, and broadband microwave‐absorbing nanocomposite based on the graphite‐like carbon nitride/CuS

Peymanfar

Karimi²,

Fallahi³

2019

J of Applied Polymer Sci

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In this study, a broadband, intense, novel, and promising microwave-absorbing nanocomposite was prepared using graphite-like carbon nitride (g-C 3 N 4 )/CuS suspended in poly(methyl methacrylate) (PMMA) medium. The g-C 3 N 4 nanosheets were synthesized by heating the urea as well as the CuS nanoparticles, and g-C 3 N 4 /CuS nanocomposites were prepared using a solvothermal method and then were separately molded by a PMMA solution to investigate their microwave-absorbing characteristics. The Fourier transform infrared and X-ray powder diffraction were used to characterize the g-C 3 N 4 , CuS, and CuS/g-C 3 N 4 nanostructures, which confirmed that the pure structure of the nanomaterials has been synthesized. The optical properties of the nanostructures were also investigated by diffuse reflection spectroscopy analysis. Accordingly, the Kubelka-Munk theory suggested significant narrow band gap for g-C 3 N 4 /CuS nanocomposite (0.27 eV), facilitating electron jumping and conductive loss. The morphology of the structures was examined using field emission scanning electron microscopy micrographs, illustrating that the uniform hexagonal structures of the CuS nanoplates have been formed and the CuS two-dimensional structures were uniformly distributed on the g-C 3 N 4 nanosheets. Finally, the microwave-absorbing properties of the CuS, g-C 3 N 4 , and g-C 3 N 4 /CuS were investigated by PMMA as a host. The microwaveabsorbing properties were evaluated using a vector network analyzer. The results illustrated that the maximum reflection loss of the g-C 3 N 4 /PMMA nanocomposite was −71.05 dB at 14.90 GHz with a thickness of 2.00 mm, demonstrating a 1.70 GHz bandwidth >30 dB, as well as g-C 3 N 4 /CuS/PMMA nanocomposite absorbed 7.30 GHz bandwidth of more than 10 dB with a thickness of 1.80 mm along the x-and ku-band frequency. The obtained results introduced the PMMA as a capable microwave-absorbing substrate. Besides, the g-C 3 N 4 /CuS/PMMA nanocomposite demonstrated metamaterial property and abundant attenuation constant.

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Z = \frac{Z_{in}}{Z_{0}} = \sqrt{\frac{μ_{r}}{ε_{r}}}

equation . Based on the results, significant impedance matching of the g‐C 3 N 4 /PMMA nanocomposite implies for its substantial microwave absorption properties.…”

Section: Resultsmentioning

confidence: 93%

Novel, promising, and broadband microwave‐absorbing nanocomposite based on the graphite‐like carbon nitride/CuS

Peymanfar

Karimi²,

Fallahi³

2019

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…3,4 Nanomaterials used as microwave absorbents could exhibit good absorbing performance and low filler content, including carbon nanotubes (CNTs), carbon nanofibers, nanosheets, nanoparticles, and nanospheres due to their size and micro-structures. [5][6][7] Carbon nanotubes (CNTs) are promising candidates for $dummy$RAMs, due to strong microwave absorption in a wide range of gigahertz frequencies. 3,[8][9][10][11] As microwave absorbers, CNTs are usually used as fillers to polymers (eg epoxy resin) to make CNT-reinforced nanocomposites which have the disadvantages of CNT entanglement in the form of agglomerates which are usually too dense to allow a complete resin impregnation.…”

Section: Introductionmentioning

confidence: 99%

Microwave absorbing properties of a radar absorbing structure composed of carbon nanotube papers/glass fabric composites

Chen

Kuo

Yang

2019

Int J Applied Ceramic Tech

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In this study, carbon nanotube papers were employed in fabricating thin and broadband radar absorbing structures (RAS). Different concentrations of the CNT papers have been made by using a vacuum filtration method, with 20 × 20 cm in size and 21‐27 μm in thickness. An epoxy resin was added into the CNT paper and then cured to become a composite with 1‐5 wt.% of CNTs and 83‐309 μm in thickness. The complex permittivity and permeability (ε′, ε″, μ′, μ″) of the CNT paper composites were measured using the transmission/reflection method in the frequency range of 2‐18 GHz. The results reveal that the real (ε′) and imaginary (ε″) parts of the complex permittivity are increased with the CNT concentration. The ε′ of 5 wt.% CNT sample reaches 323 at 2 GHz and then decreases to 49.0 at 18 GHz. The ε″ reaches 321 at 2 GHz and decreases to 26.0 at 18 GHz. The CNT paper composite combined with a glass fabric composite used for a dielectric spacer is fabricated for an innovative RAS and the reflection loss is measured using the arch method in a microwave anechoic chamber. The results show that the 5 wt.% CNT paper composite/glass fabric composite absorbers attain maximum reflection loss of −13.3 dB at 12.0 GHz, −13.8 dB at 10.0 GHz, and −16.0 dB at 7.5 GHz for spacer thickness of 1.5, 2.0, and 3.0 mm, respectively.

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“…The conductive loss is the important factor affecting the microwave absorption properties. Besides, based on the percolation theory, defined by

Z = \frac{Z_{i n}}{Z_{0}} = \sqrt{\frac{μ_{normalr}}{ϵ_{normalr}}}

equation, near the percolation point the input waves percolate more within the absorbing medium and be attenuated. The Z and C 0 of CuCr 2 O 4 /silicone rubber or PVDF and modified CuCr 2 O 4 /silicone rubber or PVDF nanocomposites in the x and ku‐band frequency have been shown in the Figure .…”

Section: Resultsmentioning

confidence: 99%

Preparation and Characterization of Copper Chromium Oxide Nanoparticles Using Modified Sol‐Gel Route and Evaluation of Their Microwave Absorption Properties

Peymanfar

Khodamoradipoor²

2019

Physica Status Solidi (a)

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In this study, simple, broadband, robust, and affordable microwave absorbing nanocomposites are prepared using CuCr2O4 nanoparticles as guests and silicone rubber or poly(vinylidene fluoride) (PVDF) as host. Firstly, the pristine and modified CuCr2O4 nanoparticles are obtained by the conventional citrate gel method in the absence and presence of sucrose as a novel capping agent in the experimental steps. X‐ray powder diffraction (XRD) patterns confirms that the CuCr2O4 nanoparticles are synthesized. Moreover, morphologies, chemical functional groups, and optical properties are studied using field emission scanning electron microscopy (FE‐SEM), Fourier transform infrared (FT‐IR), and diffuse reflection spectroscopy (DRS), respectively. The vibrating sample magnetometer (VSM) analysis reveals weak magnetic properties for the nanoparticles and confirms that the capping agent change the magnetic properties. Finally, bare and modified copper chromium oxide nanoparticles are separately molded with silicone rubber or PVDF to compare dipole and interfacial polarization. Besides, using a vector network analyzer (VNA) along the x and ku‐band frequency, novel organic precursor effects on their microwave absorption properties are examined. According to the obtained results, the maximum reflection loss of the modified CuCr2O4/PVDF is −65.57 dB at 14 GHz with 2 mm thickness and the CuCr2O4/PVDF nanocomposite absorbs a bandwidth of 7.73 GHz more than 10 dB with a thickness of 2 mm. Interestingly, novel one type filler lead to significant microwave absorbing properties as well as organic capping agent reinforced maximum microwave absorption also PVDF improves absorption bandwidth.

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Binary synergistic enhancement of dielectric and microwave absorption properties: A composite of arm symmetrical PbS dendrites and polyvinylidene fluoride

Cited by 167 publications

References 50 publications

Novel, promising, and broadband microwave‐absorbing nanocomposite based on the graphite‐like carbon nitride/CuS

Novel, promising, and broadband microwave‐absorbing nanocomposite based on the graphite‐like carbon nitride/CuS

Microwave absorbing properties of a radar absorbing structure composed of carbon nanotube papers/glass fabric composites

Preparation and Characterization of Copper Chromium Oxide Nanoparticles Using Modified Sol‐Gel Route and Evaluation of Their Microwave Absorption Properties

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