Synthesis of Magnetic Wood with Excellent and Tunable Electromagnetic Wave-Absorbing Properties by a Facile Vacuum/Pressure Impregnation Method

Lou, Zhichao; He, Hongliang; Zhou, Ming; Han, Jingquan; Cai, Jianguo; Huang, Caoxing; Zou, Jing; Zhou, Xiaoyan; Zhang, Hongjie; Sun, Zhuo

doi:10.1021/acssuschemeng.7b03332

Cited by 114 publications

(60 citation statements)

References 49 publications

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“…This interesting phenomenon is usually expressed by the 1/4 wavelength cancellation equation : Obviously, the peak frequency is inversely proportional to the thickness of absorbers. As shown in Figure S2, this sample obeys the λ/4 model, meaning the reflected electromagnetic waves from both the air-absorber interface and the absorbermetal background interface are out of phase by 180 • , making them cancel out and then resulting in a minimum RL value (Lou et al, 2018).…”

Section: Resultsmentioning

confidence: 95%

Enhanced Electromagnetic Absorption Properties of Commercial Ni/MWCNTs Composites by Adjusting Dielectric Properties

Zhao

Wang

2020

Front. Chem.

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In this manuscript, we constructed a Ni/MWCNTs absorber and properly adjusted the permittivity resulted from absorber content in the PVDF to optimize impedance matching properties. Both ε ′ and ε ′′ increase obviously with the increasing content of Ni/MWCNTs in PVDF, demonstrating that dielectric properties are dependent on the conductivity. Moderate dielectric properties and excellent impedance matching can be obtained for the filler content of 20 wt% Ni/MWCNTs. Reasonable impedance matching allows electromagnetic waves to propagate into the materials and finally realize energy dissipation through dielectric loss and interfacial polarization. As expected, the minimum reflection loss (RL) of −46.85 dB at 6.56 GHz with a low filler loading (20 wt%) and wide effective bandwidth (RL<-10 dB) of 14.0 GHz in the thickness range of 1.5-5.0 mm was obtained for the commercial Ni/MWCNTs composites, which is promising for mass production in industrial applications. Our findings offer an effective and industrialized way to design high-performance material to facilitate the research in microwave absorption.

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Section: Resultsmentioning

confidence: 95%

Enhanced Electromagnetic Absorption Properties of Commercial Ni/MWCNTs Composites by Adjusting Dielectric Properties

Zhao

Wang

2020

Front. Chem.

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“…With the rapid growth in the use of wireless electronic devices such as mobile phones, local area networks, and household robots, people’s daily life and production are increasingly affected by electromagnetic waves generated by electromagnetic systems. As a result, the society urgently needs electromagnetic wave (EMW) absorbing materials with light weight, thin thickness, wide effective absorbing band width, and strong absorption capacity [ 1 , 2 , 3 , 4 ]. These absorbers include polymer composites with low conductive nanoparticles [ 5 , 6 ], polymer composites with metallic nanoparticles [ 7 ], composites containing glass coated microwires [ 8 , 9 ], thin film based composites [ 10 , 11 ], magnetic cellulose [ 12 ], and magnetic wood [ 4 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

“…This magnetic wood has been proven to possess strong magnetic characteristics and a wave-absorption function. In addition, magnetic wood also offers a wood texture, low specific gravity, and is very easy to process, which is expected as an indoor wave absorber to extend the wood supply, improve the value of wooden products, and preserve natural resources from over-exploitation [ 4 , 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Magnetic Wood Fiber Board and Corresponding Multi-Layer Magnetic Composite Board, with Electromagnetic Wave Absorbing Properties

et al. 2018

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With the rapid growth in the use of wireless electronic devices, society urgently needs electromagnetic wave (EMW) absorbing material with light weight, thin thickness, wide effective absorbing band width, and strong absorption capacity. Herein, the multi-layer magnetic composite boards are fabricated by hot-pressing magnetic fiber boards and normal veneer layer-by-layer. The magnetic fibers obtained using in-situ chemical co-precipitation are used to fabricate magnetic fiber board by hot-pressing. The magnetic wave absorbing capacities of the magnetic fiber boards obtained with 72 h impregnation time exhibit strongest adsorption capacities of −51.01 dB with a thickness of 3.00 mm. It is proved that this outstanding EMW absorption property is due to the strongest dielectric loss, the optimal magnetic loss, and the dipole relaxation polarization. Meanwhile, the EMW absorbing capacities of the corresponding multi-layer composite magnetic board increases from −14.14 dB (3-layer) to −60.16 dB (7-layer). This is due to the generated multi-interfaces between magnetic fiber board and natural wood veneer in the EMW propagation direction, which significantly benefit multireflection and attenuation of the incident waves. The results obtained in this work indicate that natural wood fibers are of great potential in the fabrication of magnetic multi-layer boards treated as EMW absorbers via a low cost, green, and scalable method.

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“…This multilayer structure can provide large magnetic loss tangent, optimal impedance matching, and an interconnected 3D network for electromagnetic wave absorption, reflection, and attenuation. [3,21] At the start of the fabrication process, wood slices with a thickness of 3 mm were obtained by cutting a basswood block along the radial direction (tree growth direction) ( Figure S1, Supporting Information), and these slices were then used as the basic material for magnetic wood preparation. The natural wood has a pale yellow color due to the light absorption capability of lignin.…”

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confidence: 99%

“…Currently, strong EMI shielding material is in high demand for electronic devices. [3,6,31] Further EMI shielding tests were carried out using a network analyzer [phase network analyze (PNA), Agilent, E8364A], a commercial ultrawide band (UWB) antenna, and a standard horn antenna. The detailed setup is shown in Figure 6a, where the UWB antenna was covered by different types of wood shields and the horn antenna was used to receive signals coming from the UWB antenna.…”

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confidence: 99%

Lightweight and Construable Magnetic Wood for Electromagnetic Interference Shielding

et al. 2020

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Currently, booming telecom technology and digital systems bring convenience to human life and generate a large amount of electromagnetic interference (EMI), which not only affects information security but also causes harmful electromagnetic radiation pollution. [1] To address these electromagnetic pollution problems, [2,3] various EMI shielding materials have been developed. [4] Among them, iron oxide, a typical magneto-dielectric material with both magnetic loss and dielectric loss, is one of the most attractive microwave-absorbing materials. [5] However, limitations on the direct application of magneto-dielectric materials or conventional metal-based materials in EMI shielding fields still exist due to high density, high material thickness, fabrication difficulty, and unsatisfactory shielding effectiveness. [6,7] Thus, the development of ideal EMI shielding materials that are lightweight, construable, and thermally stable and have strong absorption capacities is essential and urgently needed. Wood is a natural lightweight composite that has excellent mechanical properties and unique mesostructures resulting from its natural growth. [8] One of the best features of wood is its structural anisotropy with vertically aligned channels, which are used to pump ions, water, and other ingredients through the wood trunk to meet its metabolic needs. [9] Recently, different approaches for the modification and functionalization of wood have been studied to improve wood quality and raise its added value. [10] Hu and co-workers utilized natural wood to fabricate functional transparent wood composites that exhibit extraordinary anisotropic optical and mechanical properties. [11] Yu et al. reported a simple strategy for the large-scale fabrication of artificial polymeric woods with outstanding performance, including mechanical strength comparable to that of natural wood, preferable corrosion resistance to water and acid with no decrease in the mechanical properties, as well as excellent thermal insulation and fire retardancy. [12] Yuan et al. prepared a stiff, thermally stable, and highly anisotropic carbonized wood composite with EMI shielding effectiveness by incorporating silver nanowires (AgNWs). [13] Although the carbon composite is lightweight with good EMI shielding performance, AgNWs are expensive, and a high loading of AgNWs would result in complicated processing, large amounts of agglomerates, and poor mechanical strength. For general application, wood materials usually need preservation and coloring, where the coloration is typically obtained by impregnating wood with organic pigments or coating wood sheets with toxic and volatile organic varnish. [14] These solutions are ineffective when exposed to UV radiation or heating. With the development of state-of-art techniques, iron oxide pigment has become the second most used inorganic pigment, and it includes multiple colors, such as iron oxide red, iron oxide yellow, iron

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Synthesis of Magnetic Wood with Excellent and Tunable Electromagnetic Wave-Absorbing Properties by a Facile Vacuum/Pressure Impregnation Method

Cited by 114 publications

References 49 publications

Enhanced Electromagnetic Absorption Properties of Commercial Ni/MWCNTs Composites by Adjusting Dielectric Properties

Enhanced Electromagnetic Absorption Properties of Commercial Ni/MWCNTs Composites by Adjusting Dielectric Properties

Synthesis of Magnetic Wood Fiber Board and Corresponding Multi-Layer Magnetic Composite Board, with Electromagnetic Wave Absorbing Properties

Lightweight and Construable Magnetic Wood for Electromagnetic Interference Shielding

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