Electromagnetic Interference Shielding Performances of MWCNT in Concrete Composites

2017 ◽  
Vol 266 ◽  
pp. 283-286
Author(s):  
Mahadi Sharif ◽  
Chew Sue Ping ◽  
Kin Yuen Leong
Keyword(s):  
Carbon Nanotube ◽  
Electric Field ◽  
Incident Wave ◽  
Electromagnetic Interference ◽  
Network Analyzer ◽  
Shielding Effectiveness ◽  
Frequency Range ◽  
Electromagnetic Interference Shielding ◽  
Emi Se ◽  
Shielding Material

Carbon nanotube (CNT) acts as electromagnetic interference shielding material in concrete composites was presented in this paper. Three concrete samples respectively with different CNT contents were casted and experimentally tested their shielding effectiveness (SE). The SE measurements which were obtained in function of frequency were taken using vector network analyzer (VNA) in the frequency range of 2.4 - 4.0 GHz. The experimental results showed that the CNT contributes to change in conductivity due to the positioning of the electric field of the incident wave and thus, produces different shielding performances. The EMI SE of concrete composites is improved up to 41dB with CNT concentration of 1.5-2.0 wt%.

scholarly journals Interface Engineered Microcellular Magnetic Conductive Polyurethane Nanocomposite Foams for Electromagnetic Interference Shielding

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Guolong Sang ◽  
Pei Xu ◽  
Tong Yan ◽  
Vignesh Murugadoss ◽  
Nithesh Naik ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Magnetic Loss ◽  
Interfacial Polarization ◽  
Conductive Network ◽  
Shielding Effectiveness ◽  
Electromagnetic Interference Shielding ◽  
Multiple Reflections ◽  
Conduction Loss ◽  
Composite Foams ◽  
Emi Se

Abstract Lightweight microcellular polyurethane (TPU)/carbon nanotubes (CNTs)/ nickel-coated CNTs (Ni@CNTs)/polymerizable ionic liquid copolymer (PIL) composite foams are prepared by non-solvent induced phase separation (NIPS). CNTs and Ni@CNTs modified by PIL provide more heterogeneous nucleation sites and inhibit the aggregation and combination of microcellular structure. Compared with TPU/CNTs, the TPU/CNTs/PIL and TPU/CNTs/Ni@CNTs/PIL composite foams with smaller microcellular structures have a high electromagnetic interference shielding effectiveness (EMI SE). The evaporate time regulates the microcellular structure, improves the conductive network of composite foams and reduces the microcellular size, which strengthens the multiple reflections of electromagnetic wave. The TPU/10CNTs/10Ni@CNTs/PIL foam exhibits slightly higher SE values (69.9 dB) compared with TPU/20CNTs/PIL foam (53.3 dB). The highest specific EMI SE of TPU/20CNTs/PIL and TPU/10CNTs/10Ni@CNTs/PIL reaches up to 187.2 and 211.5 dB/(g cm−3), respectively. The polarization losses caused by interfacial polarization between TPU substrates and conductive fillers, conduction loss caused by conductive network of fillers and magnetic loss caused by Ni@CNT synergistically attenuate the microwave energy.

scholarly journals A Healable and Mechanically Enhanced Composite with Segregated Conductive Network Structure for High-Efficient Electromagnetic Interference Shielding

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Ting Wang ◽  
Wei-Wei Kong ◽  
Wan-Cheng Yu ◽  
Jie-Feng Gao ◽  
Kun Dai ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Diels Alder ◽  
Electrostatic Attraction ◽  
List Type ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Electromagnetic Interference Shielding ◽  
Elongation At Break ◽  
High Efficient ◽  
Emi Se

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.

Electrically conductive and electromagnetic interference shielding of polyethylene composites with devisable carbon nanotube networks

2015 ◽  
Vol 3 (36) ◽  
pp. 9369-9378 ◽  
Author(s):  
Li-Chuan Jia ◽  
Ding-Xiang Yan ◽  
Cheng-Hua Cui ◽  
Xin Jiang ◽  
Xu Ji ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Electromagnetic Interference ◽  
Electromagnetic Interference Shielding ◽  
Electrically Conductive ◽  
Carbon Nanotube Networks ◽  
Emi Se ◽  
Segregated Structure ◽  
Polyethylene Composites

A segregated structure results in an EMI SE up to 46.4 dB in CNT/polyethylene composites with only 5 wt% CNTs.

Electromagnetic interference shielding effectiveness of polypyrrole-silver nanocomposite films on silane-modified flexible sheet

2021 ◽  
pp. 095400832110645
Author(s):  
Karim Benzaoui ◽  
Achour Ales ◽  
Ahmed Mekki ◽  
Abdelhalim Zaoui ◽  
Boudjemaa Bouaouina ◽  
...  
Keyword(s):  
Surface Treatment ◽  
Electromagnetic Interference ◽  
Nanocomposite Films ◽  
Electrical Characteristics ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Electromagnetic Interference Shielding ◽  
Silver Nanocomposite ◽  
Electromagnetic Interference Shielding Effectiveness ◽  
Emi Se

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.

Tunable electromagnetic interference shielding ability of MXene/chitosan/silver nanowire sandwich films

2021 ◽  
pp. 2151041
Author(s):  
Wei Wang ◽  
Xiaoyu Bing ◽  
Yutong Zhou ◽  
Miaomiao Geng ◽  
Yanhu Zhan ◽  
...  
Keyword(s):  
Thin Films ◽  
Electromagnetic Interference ◽  
Hybrid Composites ◽  
Core Layer ◽  
Structure Design ◽  
Silver Nanowire ◽  
Shielding Effectiveness ◽  
Electromagnetic Interference Shielding ◽  
Electromagnetic Interference Shielding Effectiveness ◽  
Emi Se

The structural design of thin films is attracting attention in academia and industry in attempts to improve electromagnetic interference shielding effectiveness (EMI SE). In this study, MXene/chitosan/silver nanowire (AgNW) sandwich films, in which the AgNW core layer was bordered by two MXene/chitosan layers, were fabricated by vacuum-assisted filtration. Because of the interconnected AgNWs in the core layer and the aligned MXene sheets in the MXene/chitosan layers, the electrical conductivity of the sandwich film reached 11,459.1 S/m. Consequently, the sandwich film exhibited an SE value of 82.3 dB. What is more, when both the AgNW and MXene contents were 33.3%, the sandwich film’s EMI SE divided by its thickness was 26,167 dB/cm, which was much superior to the values reported for inorganic hybrid composites and polymer composites filled with hybrid fillers. Such a simple approach was proved to be an effective way for further structure design of thin films in EMI shielding field.

Electromagnetic shielding effectiveness of carbon fabric/epoxy composite with continuous graphene oxide fiber and multiwalled carbon nanotube

2018 ◽  
Vol 52 (24) ◽  
pp. 3341-3350 ◽  
Author(s):  
Nuray Ucar ◽  
Burçak Karagüzel Kayaoğlu ◽  
Arınc Bilge ◽  
Gunseli Gurel ◽  
Pınar Sencandan ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Carbon Nanotube ◽  
Reduced Graphene Oxide ◽  
Electromagnetic Interference ◽  
Shielding Effectiveness ◽  
Electromagnetic Interference Shielding ◽  
Multiwalled Carbon ◽  
Oxide Fiber ◽  
Reduced Graphene ◽  
Electromagnetic Interference Shielding Effectiveness

Carbon fabric composite is used in technical applications such as aircrafts in which electromagnetic shielding (electromagnetic interference–shielding effectiveness) is required. Traditionally, metallic coatings or metal plates are used for electromagnetic shielding, however, conductive filler-filled composite is also alternative to metal sheets due to its light weight. In the literatures, there are studies about effect carbon nanotube and graphene oxide flakes on electromagnetic interference; however, there are no studies encountered that search the effect of carbon nanotube/graphene oxide fiber and alignment of graphene oxide fiber on electromagnetic interference. Thus, in this study, fabrication of light-weight carbon fabric/epoxy composite filled with graphene oxide fiber, reduced graphene oxide fiber and multiwalled carbon nanotube and alignment of graphene oxide fiber was studied for the first time for both electromagnetic shielding (electromagnetic interference–shielding effectiveness) and electrical conductivity. It was found that reduced graphene oxide with two layers at the same alignment (0–0) leads to increment in the electromagnetic interference–shielding effectiveness value, while reduced graphene oxide with opposite alignment (0–90) leads to decrease in the electromagnetic interference–shielding effectiveness value. Opposite to literatures for graphene oxide flakes, highly rough surface of graphene oxide fiber and reduced graphene oxide fiber causes a deterioration in electromagnetic interference–shielding effectiveness due to disruptive multiple reflections resulted from highly rough surface of graphene oxide fiber, which causes multiple reflection effect. Multiwalled carbon nanotube generally provides higher electromagnetic interference–shielding effectiveness than graphene-based fiber because it has higher conductivity and has no disruptive effect of crimpy surface as graphene oxide fiber. Multiwalled carbon nanotube loading of 15 wt% results to 32 dB electromagnetic interference–shielding effectiveness, which is considered an adequate and moderate level of shielding for many applications.

Microwave Irradiation of Graphene Aerogel and Its Use on the Electromagnetic Interference Shielding of BMI Nanocomposites

NANO ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. 2050143
Author(s):  
Bowen Feng ◽  
Wei Li ◽  
Fei Xue ◽  
Xingyu Tong ◽  
Jiaying Li ◽  
...  
Keyword(s):  
Self Assembly ◽  
Electromagnetic Interference ◽  
Chemical Reduction ◽  
Three Dimensional ◽  
Microwave Treatment ◽  
Shielding Effectiveness ◽  
Electromagnetic Interference Shielding ◽  
Graphene Aerogels ◽  
Electromagnetic Interference Shielding Effectiveness ◽  
Emi Se

In this work, graphene aerogels (GAs) with three-dimensional interconnected networks were prepared by chemical reduction and self-assembly of graphene oxide sheets. After microwave treatment, obtained microwave reduced graphene aerogels (MRGAs) were used in the preparation of bismaleimide (BMI) composites. The results show that the microwave treatment significantly enhanced the quality of GAs, and the three-dimensional networks in the GAs were well retained. Moreover, the MRGAs were highly efficient in endowing BMI with high electrical conductivity and excellent electromagnetic interference shielding effectiveness (EMI SE). The conductivity of MRGA/BMI composites was 42–68% higher than that of GA/BMI composites. When the filler content is 1.6 wt.%, the EMI SE of MRGA/BMI composite was 32.3% higher than that of GA/BMI composite in the X band.

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