Largely enhanced electrical properties of polymer composites via the combined effect of volume exclusion and synergy

RSC Advances ◽  
2016 ◽  
Vol 6 (57) ◽  
pp. 51900-51907 ◽  
Author(s):  
Kai Wu ◽  
Linyu Wu ◽  
Weixing Yang ◽  
Songgang Chai ◽  
Feng Chen ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Synergistic Effect ◽  
Core Shell ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
The Core ◽  
Emi Shielding Effectiveness ◽  
Core Shell Structure ◽  
Exclusion Effect

The core–shell structure of surface conductive SiO2@rGO could result in enhanced electrical conductivity and EMI shielding effectiveness as due to both synergistic effect and volume exclusion effect.

scholarly journals An anisotropic layer-by-layer carbon nanotube/boron nitride/rubber composite and its application in electromagnetic shielding

Nanoscale ◽  
2020 ◽  
Vol 12 (14) ◽  
pp. 7782-7791 ◽  
Author(s):  
Yanhu Zhan ◽  
Emanuele Lago ◽  
Chiara Santillo ◽  
Antonio Esaú Del Río Castillo ◽  
Shuai Hao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Boron Nitride ◽  
Layer By Layer ◽  
Shielding Effectiveness ◽  
Anisotropic Layer ◽  
Emi Shielding ◽  
Emi Shielding Effectiveness ◽  
Rubber Composite

A carbon nanotube/boron nitride/rubber composite with anisotropic electrical conductivity exhibits an EMI shielding effectiveness of 22.41 dB mm−1 and a thermal conductivity equal to 0.25 W m−1 K−1.

scholarly journals Carbonization of Graphene-Doped Isocyanate-Based Polyimide Foams to Achieve Carbon Foams with Excellent Electromagnetic Interference Shielding Performance

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7551
Author(s):  
Hui Jing ◽  
Zongnan Miao ◽  
Zhong Zeng ◽  
Hui Liu ◽  
Shengtai Zhou ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electromagnetic Interference ◽  
Carbonization Temperature ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Emi Shielding Effectiveness ◽  
Graphitization Degree ◽  
Carbon Foams ◽  
Potential Applications ◽  
Emi Se

Lightweight carbon foams with excellent electromagnetic interference (EMI) shielding performance were prepared by carbonization process, using isocyanate-based polyimide foams as carbon precursors. The influence of carbonization temperature and graphene-doping on the morphological, electrical and EMI shielding effectiveness (SE) of corresponding carbon foams was studied in detail. Results showed that the addition of graphene was beneficial to the improvement of electrical conductivity and EMI shielding performance of carbon foams. The electrical conductivity of carbon foams increased with the carbonization temperature which was related to the increase of graphitization degree. Collapse of foam cells was observed at higher carbonization temperatures, which was detrimental to the overall EMI SE. The optimal carbonization temperature was found at 1100 °C and the carbon foams obtained from 0.5 wt% graphene-doped foams exhibited a specific EMI SE of 2886 dB/(g/cm3), which shows potential applications in fields such as aerospace, aeronautics and electronics.

Graphene Films for Flexible EMI Shielding Materials with Cross-Linked Structure via Reaction with Diamine Monomers

NANO ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. 2050157
Author(s):  
Shaofeng lin ◽  
Qing Zheng ◽  
Bowen Lei ◽  
Jianwei Zhang ◽  
Dazhi Jiang
Keyword(s):  
Electrical Conductivity ◽  
Self Assembly ◽  
Electromagnetic Interference ◽  
Nitrogen Doping ◽  
Graphene Film ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Xps Spectra ◽  
Emi Shielding Effectiveness ◽  
Graphene Films

Three kinds of diamine monomers [ethylenediamine, butylenediamine and [Formula: see text]-phenylenediamine (PPD)] are adopted to cross-link carboxylated graphene (GP-COOH) sheets through filtration with a vacuum-assisted self-assembly technique, to fabricate highly conductive and excellent electromagnetic interference (EMI) shielding films. XRD spectroscopy of cross-linked graphene films exhibits higher interlayer [Formula: see text]-spacing than the GP-COOH film. Results of FTIR and XPS spectroscopies indicate that diamine monomers are chemically grafted to the GP-COOH sheets through nucleophilic substitution reactions. Compared with that of the GP-COOH film, electrical conductivity of the PPD-cross-linked graphene film (GP-PPD) is remarkably improved from 69.7[Formula: see text]S/cm to 248.6[Formula: see text]S/cm, attributed to the decrease of junction contact resistance between adjacent graphene sheets, nitrogen doping effect and repair of defects. Higher nitrogen content and C/O ratio are observed in the XPS spectra of the GP-PPD film, leading to higher electrical conductivity than the remaining two amine-modified graphene films. The GP-PPD film also demonstrates excellent EMI shielding performance, with EMI shielding effectiveness (SE) of 26.5 dB at a thickness of 12.5[Formula: see text][Formula: see text]m, which is also better than the others. The outstanding EMI performance of the PPD-cross-linked graphene film is mainly ascribed to the enhanced electrical conductivity and modified electronic structure with nitrogen doping.

scholarly journals Carbon Fibers Encapsulated with Nano-Copper: A Core‒Shell Structured Composite for Antibacterial and Electromagnetic Interference Shielding Applications

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 460 ◽  
Author(s):  
Yue Jiao ◽  
Caichao Wan ◽  
Wenbo Zhang ◽  
Wenhui Bao ◽  
Jian Li
Keyword(s):  
Carbon Fibers ◽  
Electromagnetic Interference ◽  
Interfacial Polarization ◽  
Core Shell ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Step Method ◽  
Water Contact ◽  
Conduction Loss ◽  
Emi Shielding Effectiveness

A facile and scalable two-step method (including pyrolysis and magnetron sputtering) is created to prepare a core‒shell structured composite consisting of cotton-derived carbon fibers (CDCFs) and nano-copper. Excellent hydrophobicity (water contact angle = 144°) and outstanding antibacterial activity against Escherichia coli and Staphylococcus aureus (antibacterial ratios of >92%) are achieved for the composite owing to the composition transformation from cellulose to carbon and nano-size effects as well as strong oxidizing ability of oxygen reactive radicals from interactions of nano-Cu with sulfhydryl groups of enzymes. Moreover, the core‒shell material with high electrical conductivity induces the interfacial polarization loss and conduction loss, contributing to a high electromagnetic interference (EMI) shielding effectiveness of 29.3 dB. Consequently, this flexible and multi-purpose hybrid of nano-copper/CDCFs may be useful for numerous applications like self-cleaning wall cladding, EMI shielding layer and antibacterial products.

scholarly journals PS/PANI/MoS2 Hybrid Polymer Composites with High Dielectric Behavior and Electrical Conductivity for EMI Shielding Effectiveness

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2690 ◽  
Author(s):  
Saboor ◽  
Khalid ◽  
Jan ◽  
Khan ◽  
Farooq ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Polymer Composites ◽  
Dielectric Behavior ◽  
Hybrid Polymer ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Emi Shielding Effectiveness ◽  
Dielectric Constant And Loss ◽  
High Dielectric

Liquid exfoliated molybdenum disulfide (MoS2) nanosheets and polyaniline (PANI) nanoparticles are dispersed in polystyrene (PS) matrix to fabricate hybrid polymer composites with high dielectric and electromagnetic interference (EMI) shielding behavior. A phase-separated morphology is formed when PANI and MoS2 are incorporated into polystyrene (PS) matrix. An increasing concentration of MoS2 nanoparticles inside PS/PANI (5 wt %) polymer blend forms an interconnected network, resulting in high electrical conductivity and dielectric behavior, making them a suitable candidate for EMI shielding application. An increment in dielectric constant and loss, up to four and five orders of magnitude, respectively, is recorded at a maximum concentration of 1 wt % of MoS2 in PS/PANI-5 polymer blend at 100 Hz. The enhanced dielectric characteristics for PS/PANI/MoS2 composites are then theoretically evaluated for the estimation of EMI shielding effectiveness in the frequency range of 100 Hz to 5 MHz. The maximum dielectric constant and loss achieved for PS/PANI-5 wt %/MoS2-1 wt % are responsible for estimated shielding effectiveness of around 92 dB at 100 Hz. The increase in dielectric behavior and shielding effectiveness is probably due to the increased number of charged dipoles accumulated at the insulator–conductor interface.

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