EMI Shielding Effectiveness of Carbon Nanotube BuckyPaper Nanocomposite/Foam Sandwich Structures

2006 ◽  
Author(s):  
Ben Wang ◽  
Richard Liang ◽  
Olivier Marietta-Tondin ◽  
Sheng Wang ◽  
Chuck Zhang ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Composite Structures ◽  
Large Scale ◽  
Sandwich Structures ◽  
Control Panel ◽  
Technical Solution ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Frequency Range ◽  
Entire Frequency Range

Carbon nanotubes are known for their exceptional mechanical, electrical and thermal properties. Nanotubes’ electrical properties will play a vital role in many critical applications, with EMI shielding as one of the more important applications. In this study, the authors examined the effectiveness of SWNT BuckyPaper films’ electromagnetic interference (EMI) shielding. Individual BuckyPaper films used in the research were only 15∼25μm thick with an area density of 0.0705 oz./ft2 or 21.5g/m2. Highly conductive SWNT BuckyPapers films were incorporated into foam sandwich structures. EMI tests revealed that the foam structures with a surface skin of two layers of randomly oriented BuckyPaper films achieved attenuation as great as 26 dB at 455–500 MHz or an average of 21 dB across the entire frequency range, compared to the pure foam control panel. At frequency ranges of 4GHz-18GHz, the foam sandwich samples with three layers SWNT BuckyPapers showed an EMI attenuation as high as 30dB across the entire frequency range. The results show that SWNT BuckyPaper materials offer a very promising lightweight technical solution for EMI shielding application. BuckyPapers can also easily be incorporated into conventional composite structures, which is critical for potential large scale application of SWNTs for multifunctional composites and structures.

Electromagnetic Interference Shielding Characteristics of Carbon Nanofiber-Polymer Composites

2007 ◽  
Vol 7 (2) ◽  
pp. 549-554
Author(s):  
Yonglai Yang ◽  
Mool C. Gupta ◽  
Kenneth L. Dudley ◽  
Roland W. Lawrence
Keyword(s):  
Electromagnetic Interference ◽  
Carbon Nanofiber ◽  
Frequency Region ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Frequency Range ◽  
Electromagnetic Interference Shielding ◽  
Emi Shielding Effectiveness ◽  
Frequency Independent ◽  
Ku Band

Electromagnetic interference (EMI) shielding characteristics of carbon nanofiber-polystyrene composites were investigated in the frequency range of 12.4–18 GHz (Ku-band). It was observed that the shielding effectiveness of such composites was frequency independent, and increased with increasing carbon nanofiber loading within Ku-band. The experimental data exhibited that the shielding effectiveness of the polymer composite containing 20 wt% carbon nanofibers could reach more than 36 dB in the measured frequency region, indicating such composites can be applied to the potential EMI shielding materials. In addition, the results showed that the contribution of reflection to the EMI shielding effectiveness was much larger than that of absorption, implying the primary EMI shielding mechanism of such composites was reflection of electromagnetic radiation within Ku-band.

EMI Shielding Effectiveness of CNTs Composites

2013 ◽  
Vol 331 ◽  
pp. 439-442 ◽  
Author(s):  
Ping Li ◽  
Aik Seng Low ◽  
Yue Yan Shan ◽  
Guat Choon Ong ◽  
Xi Jiang Yin
Keyword(s):  
Carbon Nanotubes ◽  
Electromagnetic Interference ◽  
Conductive Network ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Frequency Range ◽  
Electromagnetic Interference Shielding ◽  
Emi Shielding Effectiveness ◽  
Electromagnetic Interference Shielding Effectiveness ◽  
5 Ghz

A carbon nanotubes (CNTs) composite and its electromagnetic interference shielding effectiveness (SE) were investigated. Its absorptance, reflectance and shielding effectiveness (SE) were analysed. The CNTs composite has a shielding effectiveness (SE) of more than 25 dB (>99.68%) in frequency range from 30 MHz to 5 GHz. The testing results also demonstrate that the shielding mechanism of the CNTs composite is mainly EMI absorption of electromagnitic radiation. The high SE of the CNTs composite in the study is attributed to a high aspect ratio (>3000) and good conductive network of CNTs within the composite.

Electromagnetic Interference Shielding Characteristics of Carbon Nanofiber-Polymer Composites

2007 ◽  
Vol 7 (2) ◽  
pp. 549-554 ◽  
Author(s):  
Yonglai Yang ◽  
Mool C. Gupta ◽  
Kenneth L. Dudley ◽  
Roland W. Lawrence
Keyword(s):  
Electromagnetic Interference ◽  
Carbon Nanofiber ◽  
Frequency Region ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Frequency Range ◽  
Electromagnetic Interference Shielding ◽  
Emi Shielding Effectiveness ◽  
Frequency Independent ◽  
Ku Band

Electromagnetic interference (EMI) shielding characteristics of carbon nanofiber-polystyrene composites were investigated in the frequency range of 12.4–18 GHz (Ku-band). It was observed that the shielding effectiveness of such composites was frequency independent, and increased with increasing carbon nanofiber loading within Ku-band. The experimental data exhibited that the shielding effectiveness of the polymer composite containing 20 wt% carbon nanofibers could reach more than 36 dB in the measured frequency region, indicating such composites can be applied to the potential EMI shielding materials. In addition, the results showed that the contribution of reflection to the EMI shielding effectiveness was much larger than that of absorption, implying the primary EMI shielding mechanism of such composites was reflection of electromagnetic radiation within Ku-band.

scholarly journals Nanostructured La0.7Sr0.3MnO3 compounds for effective electromagnetic interference shielding in the X-band frequency range

2015 ◽  
Vol 3 (4) ◽  
pp. 820-827 ◽  
Author(s):  
Hilal Ahmad Reshi ◽  
Avanish P. Singh ◽  
Shreeja Pillai ◽  
Rama Shankar Yadav ◽  
S. K. Dhawan ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Frequency Range ◽  
Electromagnetic Interference Shielding ◽  
Band Frequency ◽  
Emi Shielding Effectiveness ◽  
X Band

EMI shielding effectiveness values of up to 19 dB are observed in LSMO nanomaterials.

Effect of dielectric and magnetic nanofillers on electromagnetic interference shielding effectiveness of carbon/epoxy composites

2021 ◽  
pp. 002199832110526
Author(s):  
Hafiz Shehbaz Ahmad ◽  
Tanveer Hussain ◽  
Yasir Nawab ◽  
Shuaib Salamat
Keyword(s):  
Silicon Carbide ◽  
Zinc Oxide ◽  
Electromagnetic Interference ◽  
Electronic Devices ◽  
Skin Depth ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Frequency Range ◽  
Electromagnetic Pollution ◽  
Emi Se

Tremendous development in electronic devices and their indiscriminate use has created a severe problem of electromagnetic pollution. Different types of electromagnetic interference (EMI) shielding materials and structures are used to protect electronic devices from the harmful effect of electromagnetic pollution. A present study was conducted to compare the effect of dielectric and magnetic nanofillers on electromagnetic shielding effectiveness (EMI SE) of carbon fiber reinforced composite structures (CFRC). Composites structures were developed using different dielectric and magnetic nanofillers. Effect of nanofillers on microwave absorption properties and reduction in electromagnetic pollution was investigated. Relationship between electrical conductivity and EMI shielding effectiveness in L, S, C, and X-frequency range was also studied. Among the dielectric nanofillers, silicon carbide showed excellent EMI SE in X-frequency range, while among magnetic nanofillers, zinc oxide showed excellent EMI shielding characteristics in a broad frequency range of 100 MHz to 13.6 GHz. Among magnetic nanofillers, CFRC with zinc oxide nanofillers showed the lowest skin depth value of 3.32 × 10−4 mm and among dielectric nanofiller, CFRC with silicon carbide nanofillers gave the lowest skin depth value of 6.49 × 10−4 mm, implying their excellent potential in EMI shielding applications.

Electrical Conductivity and Electromagnetic Interference Shielding of Multi-walled Carbon Nanotube Filled Polymer Composites

2004 ◽  
Vol 858 ◽  
Author(s):  
Yonglai Yang ◽  
Mool C. Gupta ◽  
Kenneth L. Dudley ◽  
Roland W. Lawrence
Keyword(s):  
Carbon Nanotube ◽  
Electromagnetic Interference ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Frequency Range ◽  
Sem Images ◽  
Percolation Behavior ◽  
Multi Walled Carbon Nanotube ◽  
X Band ◽  
Conducting Networks

ABSTRACTMulti-walled carbon nanotube (MWNT) filled polystyrene (PS) composites were synthesized for electromagnetic interference (EMI) shielding applications. SEM images of composites showed the formation of the conducting networks through MWNTs within the PS matrix. The measured DC conductivity of composites increased with increasing MWNT loading, showing a typical percolation behavior. EMI shielding characteristics of MWNT-PS composites were investigated in the frequency range of 8.2–12.4 GHz (X-band). It was observed that the shielding effectiveness (SE) of such composite increased with the increase of MWNT loading. The SE of the composite containing 7 wt% MWNTs could reach more than 26 dB in the measured frequency region.

Hybrid Nanocomposite Material for EMI Shielding in Spacecrafts

2015 ◽  
Vol 1101 ◽  
pp. 46-50 ◽  
Author(s):  
Fawad Tariq ◽  
Madni Shifa ◽  
Mateen Tariq ◽  
S. Kazim Hasan ◽  
Rasheed Ahmed Baloch
Keyword(s):  
Electrical Conductivity ◽  
Electromagnetic Interference ◽  
Hybrid Nanocomposite ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Frequency Range ◽  
Multiwalled Carbon ◽  
Emi Shielding Effectiveness ◽  
The Matrix ◽  
Emi Se

In this study lightweight carbon fiber and multiwalled carbon nanotubes filled hybrid nanocomposite was fabricated for electromagnetic interference (EMI) shielding in spacecraft. Electrical conductivity was conducted to assess the affect of MWCNT addition on composite. EMI shielding effectiveness (SE) was tested in the frequency range of 1-18 GHz. Comparison of SE was also made with AA6061-T6 sheet. Dispersion of nanotubes in the matrix was examined through microscopy. Results indicated that the conductivity was increased with increasing MWCNTs up to 0.25 wt%. Higher loading level of MWCNTs has resulted in decrease in conductivity due to agglomeration in cured samples. Hybrid nanocomposite exhibited improved SE than AA6061-T6 in 1-8 GHz frequency range. Best SE and electrical conductivity was witnessed in 0.25 wt% MWCNT sample. EMI SE in range of-20 dB to-40 dB can be easily achieved in our developed material.

scholarly journals Ultrathin, Lightweight, and Flexible CNT Buckypaper Enhanced Using MXenes for Electromagnetic Interference Shielding

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Rongliang Yang ◽  
Xuchun Gui ◽  
Li Yao ◽  
Qingmei Hu ◽  
Leilei Yang ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
High Performance ◽  
Electronic Devices ◽  
Deposition Process ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Emi Shielding Effectiveness ◽  
X Band ◽  
Wearable Electronic Devices ◽  
Emi Se

AbstractLightweight, flexibility, and low thickness are urgent requirements for next-generation high-performance electromagnetic interference (EMI) shielding materials for catering to the demand for smart and wearable electronic devices. Although several efforts have focused on constructing porous and flexible conductive films or aerogels, few studies have achieved a balance in terms of density, thickness, flexibility, and EMI shielding effectiveness (SE). Herein, an ultrathin, lightweight, and flexible carbon nanotube (CNT) buckypaper enhanced using MXenes (Ti3C2Tx) for high-performance EMI shielding is synthesized through a facile electrophoretic deposition process. The obtained Ti3C2Tx@CNT hybrid buckypaper exhibits an outstanding EMI SE of 60.5 dB in the X-band at 100 μm. The hybrid buckypaper with an MXene content of 49.4 wt% exhibits an EMI SE of 50.4 dB in the X-band with a thickness of only 15 μm, which is 105% higher than that of pristine CNT buckypaper. Furthermore, an average specific SE value of 5.7 × 104 dB cm2 g−1 is exhibited in the 5-μm hybrid buckypaper. Thus, this assembly process proves promising for the construction of ultrathin, flexible, and high-performance EMI shielding films for application in electronic devices and wireless communications.

Dual percolations of electrical conductivity and electromagnetic interference shielding in progressively agglomerated CNT/polymer nanocomposites

2021 ◽  
pp. 108128652110214
Author(s):  
Xiaodong Xia ◽  
George J. Weng
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Polymer Nanocomposites ◽  
Electromagnetic Interference ◽  
Effective Medium Theory ◽  
Scale Model ◽  
Shielding Effectiveness ◽  
Emi Shielding

Recent experiments have revealed two distinct percolation phenomena in carbon nanotube (CNT)/polymer nanocomposites: one is associated with the electrical conductivity and the other is with the electromagnetic interference (EMI) shielding. At present, however, no theories seem to exist that can simultaneously predict their percolation thresholds and the associated conductivity and EMI curves. In this work, we present an effective-medium theory with electrical and magnetic interface effects to calculate the overall conductivity of a generally agglomerated nanocomposite and invoke a solution to Maxwell’s equations to calculate the EMI shielding effectiveness. In this process, two complex quantities, the complex electrical conductivity and complex magnetic permeability, are adopted as the homogenization parameters, and a two-scale model with CNT-rich and CNT-poor regions is utilized to depict the progressive formation of CNT agglomeration. We demonstrated that there is indeed a clear existence of two separate percolative behaviors and showed that, consistent with the experimental data of poly-L-lactic acid (PLLA)/multi-walled carbon nanotube (MWCNT) nanocomposites, the electrical percolation threshold is lower than the EMI shielding percolation threshold. The predicted conductivity and EMI shielding curves are also in close agreement with experimental data. We further disclosed that the percolative behavior of EMI shielding in the overall CNT/polymer nanocomposite can be illustrated by the establishment of connective filler networks in the CNT-poor region. It is believed that the present research can provide directions for the design of CNT/polymer nanocomposites in the EMI shielding components.

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.

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