Sustainable wood-based composites for microwave absorption and electromagnetic interference shielding

2020 ◽  
Vol 8 (46) ◽  
pp. 24267-24283 ◽  
Author(s):  
Ming Zhou ◽  
Weihua Gu ◽  
Gehuan Wang ◽  
Jing Zheng ◽  
Chunchuan Pei ◽  
...  

In this review, wood-based composites for efficient EMI shielding and MA are comprehensively introduced.

Author(s):  
Xianfeng Yang ◽  
You Zhou ◽  
Hongna Xing ◽  
Hongpeng Wang ◽  
Wei Feng ◽  
...  

Abstract Dual-functional magnetic/dielectric Fe/Fe3C@C composites were fabricated by pyrolysis of MIL-88B (Fe) in Ar atmosphere, which was used for microwave absorption and electromagnetic interference (EMI) shielding. The Fe/Fe3C nanocrystals were completely encapsulated in crystalline carbon, which can improve the oxidation resistance capacity. Owing to the remarkable impedance matching and strong attenuation constants, Fe/Fe3C@C composites show an optimal RL value of -56.4 dB at 14.0 GHz and broad effective absorption bandwidth (RL ≤ -10 dB) of 4.8 GHz, when the filling ratio and absorber thickness are only 20 wt% and 1.9 mm, respectively. Resulted from the high conductivity of crystalline carbon, magnetic loss of Fe/Fe3C and core-shell structure, the Fe/Fe3C@C composites also show remarkable EMI shielding properties at X band, which are enhanced by increasing the filling ratio of Fe/Fe3C@C composites. When the filling ratio was 50 wt%, the EMI shielding efficiency can reach 35 dB. This work suggests that the magnetic/dielectric Fe/Fe3C@C is a good cadidate in microwave absorption and electromagnetic interference shielding.


RSC Advances ◽  
2021 ◽  
Vol 11 (30) ◽  
pp. 18476-18482
Author(s):  
Licui Wang ◽  
Zhaoxin Xie ◽  
Yanhu Zhan ◽  
Xuehui Hao ◽  
Yanyan Meng ◽  
...  

It is of great significance for electromagnetic interference (EMI) shielding materials to fulfill long-lasting service requirements.


2021 ◽  
Author(s):  
Runxiao Chen ◽  
Rongrong Yu ◽  
Xiaoyuan Pei ◽  
Wei Wang ◽  
Diansen Li ◽  
...  

The extensive use of electrical equipment and portable electronics has aroused major concerns about electromagnetic pollution. Carbon-based polymer composites are widely used in the electromagnetic interference (EMI) shielding field, motivated...


Nanoscale ◽  
2021 ◽  
Author(s):  
Bing Zhou ◽  
Qingtao Li ◽  
Penghui Xu ◽  
Yuezhan Feng ◽  
Jianmin Ma ◽  
...  

Flexible cellulose-based conductive films reveal the high potential in electromagnetic interference (EMI) shielding and thermal management applications. However, the high contact electrical/thermal resistance in these films is still one of...


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Xinyu Wu ◽  
Tingxiang Tu ◽  
Yang Dai ◽  
Pingping Tang ◽  
Yu Zhang ◽  
...  

Highlights 3D printing of MXene frames with tunable electromagnetic interference shielding efficiency is demonstrated. Highly conductive MXene frames are reinforced by cross-linking with aluminum ions. Electromagnetic wave is visualized by electromagnetic-thermochromic MXene patterns. Abstract The highly integrated and miniaturized next-generation electronic products call for high-performance electromagnetic interference (EMI) shielding materials to assure the normal operation of their closely assembled components. However, the most current techniques are not adequate for the fabrication of shielding materials with programmable structure and controllable shielding efficiency. Herein, we demonstrate the direct ink writing of robust and highly conductive Ti3C2Tx MXene frames with customizable structures by using MXene/AlOOH inks for tunable EMI shielding and electromagnetic wave-induced thermochromism applications. The as-printed frames are reinforced by immersing in AlCl3/HCl solution to remove the electrically insulating AlOOH nanoparticles, as well as cross-link the MXene sheets and fuse the filament interfaces with aluminum ions. After freeze-drying, the resultant robust and porous MXene frames exhibit tunable EMI shielding efficiencies in the range of 25–80 dB with the highest electrical conductivity of 5323 S m−1. Furthermore, an electromagnetic wave-induced thermochromic MXene pattern is assembled by coating and curing with thermochromic polydimethylsiloxane on a printed MXene pattern, and its color can be changed from blue to red under the high-intensity electromagnetic irradiation. This work demonstrates a direct ink printing of customizable EMI frames and patterns for tuning EMI shielding efficiency and visualizing electromagnetic waves.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Ting Wang ◽  
Wei-Wei Kong ◽  
Wan-Cheng Yu ◽  
Jie-Feng Gao ◽  
Kun Dai ◽  
...  

Highlights The cationic waterborne polyurethanes microspheres with Diels-Alder bonds were synthesized for the first time. The electrostatic attraction not only endows the composite with segregated structure to gain high electromagnetic-interference shielding effectiveness, but also greatly enhances mechanical properties. Efficient healing property was realized under heating environment. Abstract It is still challenging for conductive polymer composite-based electromagnetic interference (EMI) shielding materials to achieve long-term stability while maintaining high EMI shielding effectiveness (EMI SE), especially undergoing external mechanical stimuli, such as scratches or large deformations. Herein, an electrostatic assembly strategy is adopted to design a healable and segregated carbon nanotube (CNT)/graphene oxide (GO)/polyurethane (PU) composite with excellent and reliable EMI SE, even bearing complex mechanical condition. The negatively charged CNT/GO hybrid is facilely adsorbed on the surface of positively charged PU microsphere to motivate formation of segregated conductive networks in CNT/GO/PU composite, establishing a high EMI SE of 52.7 dB at only 10 wt% CNT/GO loading. The Diels–Alder bonds in PU microsphere endow the CNT/GO/PU composite suffering three cutting/healing cycles with EMI SE retention up to 90%. Additionally, the electrostatic attraction between CNT/GO hybrid and PU microsphere helps to strong interfacial bonding in the composite, resulting in high tensile strength of 43.1 MPa and elongation at break of 626%. The healing efficiency of elongation at break achieves 95% when the composite endured three cutting/healing cycles. This work demonstrates a novel strategy for developing segregated EMI shielding composite with healable features and excellent mechanical performance and shows great potential in the durable and high precision electrical instruments.


2021 ◽  
pp. 095400832110645
Author(s):  
Karim Benzaoui ◽  
Achour Ales ◽  
Ahmed Mekki ◽  
Abdelhalim Zaoui ◽  
Boudjemaa Bouaouina ◽  
...  

The conventional electromagnetic interference (EMI) shielding materials are being gradually replaced by a new generation of supported conducting polymer composites (CPC) films due to their many advantages. This work presents a contribution on the effects of silane surface–modified flexible polypyrrole-silver nanocomposite films on the electromagnetic interference shielding effectiveness (EMI-SE). Thus, the UV-polymerization was used to in-situ deposit the PPy-Ag on the biaxial oriented polyethylene terephthalate (BOPET) flexible substrates whose surfaces were treated by 3-aminopropyltrimethoxysilane (APTMS). X-ray Photoelectron Spectroscopy (XPS) analyzes confirmed the APTMS grafting procedure. Structural, morphological, thermal, and electrical characteristics of the prepared films were correlated to the effect of substrate surface treatment. Thereafter, EMI-SE measurements of the elaborated films were carried out as per ASTM D4935 standard for a wide frequency band extending from 50 MHz to 18 GHz. The obtained results confirmed that the APTMS-treated BOPET film exhibit higher EMI shielding performance and better electrical characteristics compared to the untreated film. In fact, a 32% enhancement of EMI-SE was noted for the treated films compared to the untreated ones. Overall, these results put forward the role played by the surface treatment in strengthening the position of flexible PPy-Ag supported films as high-performance materials in electronic devices and electromagnetic interference shielding applications.


Author(s):  
kexia Jin ◽  
Jianxiong Xing ◽  
Xinge Liu ◽  
Zehui Jiang ◽  
Shumin Yang ◽  
...  

To achieve high mechanical strength electromagnetic interference (EMI) shielding materials for practical application, cellulose nanocrystals (CNC) as a reinforcing and dispersing agent, are intercalated into reduced graphene oxide (RGO) layers,...


2017 ◽  
Vol 5 (5) ◽  
pp. 1095-1105 ◽  
Author(s):  
Jun Li ◽  
Hu Liu ◽  
Jiang Guo ◽  
Zhen Hu ◽  
Zhijiang Wang ◽  
...  

Flexible lightweight conductive nanocomposites prepared by self-assembly of gold nanoparticles on charged polymer nanofibers show enhanced EMI shielding effectiveness and mechanical properties.


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