The effect of polyethylenimine on the microwave absorbing properties of a hybrid microwave absorber of Fe3O4/MWNTs

Zhang, Aibo; Meng, Tao; Cao, Xiufen; Lu, Zhengbin; Shen, Yongtao

doi:10.1007/s10853-014-8165-8

Cited by 24 publications

(5 citation statements)

References 21 publications

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“…It is clear that the addition of MWCNTs does not change the crystal structure of the FeSiAl alloy. When the MWCNT content is 10 wt.%, characteristic diffraction peaks at 26.3° and 43.4° from MWCNTs can be clearly detected 29 .…”

Section: Resultsmentioning

confidence: 97%

Flaky FeSiAl alloy-carbon nanotube composite with tunable electromagnetic properties for microwave absorption

Huang

Liu

Chuai

et al. 2016

Sci Rep

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Flaky FeSiAl alloy/multi-wall carbon nanotube (FeSiAl/MWCNT) composite was fabricated by facile and scalable ball milling method. The morphology and electromagnetic properties of the FeSiAl alloy can be well tuned by controlling the milling time. It is found that the magnetic loss of the FeSiAl alloy is improved by optimizing the milling time due to the increased anisotropy field. Meanwhile the addition of MWCNTs enhances the dielectric loss of the composite by increasing the interfacial polarizations, dipolar polarizations and conductive paths. Relative to conventional FeSiAl absorbers, the FeSiAl/MWCNT composite exhibits greatly improved microwave absorption performance with advantages of strong absorption and small thickness. The minimum reflection loss of the composite reaches −42.8 dB at 12.3 GHz at a very thin thickness of 1.9 mm.

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Section: Resultsmentioning

confidence: 97%

Flaky FeSiAl alloy-carbon nanotube composite with tunable electromagnetic properties for microwave absorption

Huang

Liu

Chuai

et al. 2016

Sci Rep

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“…As we know, microwave absorbing properties of the samples can be estimated by the reflection loss (RL) curves. − According to the transmission line theory, the reflection loss (RL) values of as-synthesized samples can be deduced from the following equations: where Z in refers to the normalized input impedance of a metal-backed microwave absorption layer, c is the velocity of light in free space, f is the frequency of the wave and d is the layer thickness. Additionally, the relative complex permittivity (ε r ) and relative permeability (μ r ) of the composite medium are expressed as ε r = ε′ – j ε″, μ r = μ′ – j μ″.…”

Section: Results and Discussionmentioning

confidence: 99%

Well-Defined Core–Shell Fe₃O₄@Polypyrrole Composite Microspheres with Tunable Shell Thickness: Synthesis and Their Superior Microwave Absorption Performance in the Ku Band

Qiao

Lei

et al. 2016

Ind. Eng. Chem. Res.

132

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Highly regulated core−shell Fe 3 O 4 @polypyrrole composite microspheres have been successfully prepared via chemical oxidative polymerization in the presence of poly(vinyl alcohol) and p-toluenesulfonic acid. The polypyrrole shell thickness can be adjusted from 20 to 80 nm with the variation of the pyrrole/Fe 3 O 4 ratio. Investigations of the microwave absorbing properties indicate that the polypyrrole shell plays an important role, and the maximum reflection loss of composite microspheres can reach as much as −31.5 dB (>99.9% absorption) at 15.5 GHz with a matching layer thickness of 2.5 mm. Compared to the physically blended Fe 3 O 4 −PPy composites, Fe 3 O 4 @polypyrrole composite microspheres not only possess better reflection loss performance but also have a wider absorbing bandwidth of 5.2 GHz (12.8−18 GHz) in the Ku band, which may be attributed to the intensive synergistic effect of dielectric loss from polypyrrole shells and magnetic loss from Fe 3 O 4 cores. Therefore, regulated core−shell Fe 3 O 4 @polypyrrole composite microspheres are postulated to be more promising in microwave absorption applications.

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“…1,2 Microwave absorption materials can minimize the electromagnetic reection from metal plates such as those in aircras, ships, tanks, and the walls of anechoic chambers and electronic equipment. 3 Microwave absorption materials are divided into dielectric loss materials and magnetic loss materials according to the microwave absorbing mechanism. MWNTs are dielectric loss absorbents.…”

Section: Introductionmentioning

confidence: 99%

The effect of polymer polarity on the microwave absorbing properties of MWNTs

Zhang

et al. 2015

RSC Adv.

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Two different polarity polymers, polyvinylpyrrolidone (PVP) and polyethyleneimine (PEI) with the same molecular weight were selected to modify the surface of MWNTs using a non-covalent method. The aim was to investigate the effect of polymer polarity on the microwave absorbing properties of MWNTs. The polarization effects of PVP and PEI on MWNTs were simulated by the Cole-Cole semicircle model. The structure and morphology of polymer modified MWNTs were characterized by FTIR, TGA, Raman spectroscopy, SEM and TEM. The SEM and TEM results demonstrated that the addition of PVP and PEI could prevent MWNTs from aggregating and was helpful for the improvement of the dispersion of MWNTs. The excellent microwave absorbing properties could be obtained by adjusting the mass percentage of polymer/MWNTs hybrids in paraffin wax. The results showed that both PVP/MWNTs and PEI/MWNTs hybrids had good microwave absorption (<À7 dB) in the X-band frequency when the mass percentage of polymer/MWNTs in paraffin wax was 30%. However, the maximum reflection loss (RL) of PVP/MWNTs hybrids was larger than that of PEI/MWNTs hybrids. The maximum RL of PVP/MWNTs was À23.84 dB, while the maximum RL of PEI/MWNTs was about À21.01 dB. Moreover, the polymer polarity had an impact on the response frequency where the maximum RL appeared. The RL peak values of PVP/ MWNTs hybrids appeared at 10.48 GHz, while it was at 8.96 GHz for the PEI/MWNTs hybrids. The results indicated that the polymer polarity had a significant influence on the microwave absorbing properties and microwave absorbing response frequency of MWNTs.

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The effect of polyethylenimine on the microwave absorbing properties of a hybrid microwave absorber of Fe3O4/MWNTs

Cited by 24 publications

References 21 publications

Flaky FeSiAl alloy-carbon nanotube composite with tunable electromagnetic properties for microwave absorption

Flaky FeSiAl alloy-carbon nanotube composite with tunable electromagnetic properties for microwave absorption

Well-Defined Core–Shell Fe₃O₄@Polypyrrole Composite Microspheres with Tunable Shell Thickness: Synthesis and Their Superior Microwave Absorption Performance in the Ku Band

The effect of polymer polarity on the microwave absorbing properties of MWNTs

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The effect of polyethylenimine on the microwave absorbing properties of a hybrid microwave absorber of Fe3O4/MWNTs

Cited by 24 publications

References 21 publications

Flaky FeSiAl alloy-carbon nanotube composite with tunable electromagnetic properties for microwave absorption

Flaky FeSiAl alloy-carbon nanotube composite with tunable electromagnetic properties for microwave absorption

Well-Defined Core–Shell Fe3O4@Polypyrrole Composite Microspheres with Tunable Shell Thickness: Synthesis and Their Superior Microwave Absorption Performance in the Ku Band

The effect of polymer polarity on the microwave absorbing properties of MWNTs

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Product

Resources

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Well-Defined Core–Shell Fe₃O₄@Polypyrrole Composite Microspheres with Tunable Shell Thickness: Synthesis and Their Superior Microwave Absorption Performance in the Ku Band