Low percolation threshold and electromagnetic shielding effectiveness of nano-structured carbon based ethylene methyl acrylate nanocomposites

Mondal, Subhadip; Ganguly, Sayan; Das, Poushali; Khastgir, Dipak; Das, Narayan Ch.

doi:10.1016/j.compositesb.2017.03.022

Cited by 143 publications

(78 citation statements)

References 101 publications

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“…For the CNT/ PVDF composites, the permittivities stepwisely increase with increasing CNT content when the CNT content is below 3.5 wt%. However, when the CNT content exceeds 3.5 wt%, negative permittivity which stems from the plasma oscillation of free electrons in percolative CNT networks when the CNT content approaches percolation threshold appears [52,[65][66][67][68]. And the absolute value of negative permittivity increases with increasing CNT content owing to the enhanced effective concentration of delocalized electron in CNT/PVDF composites according to Drude's model [69].…”

Section: Resultsmentioning

confidence: 99%

Improved dielectric permittivity and retained low loss in layer-structured films via controlling interfaces

Mao

Shi

Wang

et al. 2018

Adv Compos Hybrid Mater

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The search for high-performance dielectric materials has long been driven by the urgent needs for various modern electronics. However, enhanced permittivity is always accompanied by elevated loss, which seriously hinders the development and applications of dielectric materials. Herein, negative-k layers were introduced into layer-structured films, forming a new class of multilayer composites consisting of alternately stacked positive-k and negative-k layers. Compared with traditional multilayer composites without negative-k layers, the layered composites containing extra positive-k/negative-k interfaces exhibit superior ability in balancing the contradict parameters: permittivity and loss, yielding substantially enhanced permittivity without sacrificing the low loss. It is indicated that the permittivity was enhanced by the charge accumulations and reinforced polarizations on the interfaces between positive-k and negative-k layers. Meanwhile, the loss induced by the leakage current was suppressed by the blocked transport of carriers between adjacent layers. The trilayered 60-3.5-60 composite exhibits an enhanced dielectric constant (ε′ ≈ 33 @10 kHz) and retained low loss (tanδ ≈ 0.12 @10 kHz) compared with the single-layer BT/PVA composite containing 60 wt% BT fillers (ε′ ≈ 9.5 @10 kHz, tanδ ≈ 0.075 @10 kHz). This research offers an effective way to design and fabricate novel high-performance dielectric materials.

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Section: Resultsmentioning

confidence: 99%

Improved dielectric permittivity and retained low loss in layer-structured films via controlling interfaces

Mao

Shi

Wang

et al. 2018

Adv Compos Hybrid Mater

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“…Since a long period of time, metals have been used as EMI shielding materials but upcoming trend shifts towards polymer nanocomposites because of their light weight, noncorrosive nature and low price . Polymer nanocomposites fabricated with carbonaceous materials such as graphite, single and multiwall carbon nanotube (CNT), carbon fiber, and carbon black have been widely used as EMI shielding materials . Although use of expandable graphite, carbon nanofibers, and graphene nanoplatelets have been extensively used to reduce electrical percolation via the formation of conductive network through polymer matrices and offer necessary EMI shielding for commercialization, but they have limitations in processing, poor dispersion, and high production cost .…”

Section: Introductionmentioning

confidence: 99%

Mechanically robust conductive carbon clusters confined ethylene methyl acrylate–based flexible composites for superior shielding effectiveness

Bhawal

Ganguly

Das

et al. 2017

Polymers for Advanced Techs

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Arresting of conducting carbon black into polymeric matrix to develop flexible and light weight composite has been a widely practiced platform. Extensive development of telecommunication creates a major vexations regarding radiation pollution. Thereafter EMA (Ethylene methyl acrylate) is a commercially available polymer, which has high strength to weight ratio, ageing and weather resistance, wide range of application temperature, lower density in comparison with the major plastics, and very low temperature flexibility even in

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“…The heat and EM radiation have an inherent connection-absorption of EM waves by any material results in its heating. Several studies reported the use of carbon fibers, [22][23][24][25][26][27][28][29] carbon black, [30,31] bulk graphite, [32][33][34] carbon nanotubes (CNT), [16,17,[35][36][37][38][39] reduced graphene oxide (rGO), [2,6,[40][41][42][43][44][45][46][47][48][49][50] graphene, [51][52][53][54] and combination of carbon allotropes with orThe synthesis and characterization of epoxy-based composites with few-layer graphene fillers, which are capable of dual-functional applications, are reported. The conventional approach for handling the heat and EM radiation problems is based on utilization of the thermal interface materials (TIM), which can spread the heat, and electromagnetic interference (EMI) shielding materials, which can protect from EM waves.…”

mentioning

confidence: 99%

Dual‐Functional Graphene Composites for Electromagnetic Shielding and Thermal Management

Kargar

Barani

Balinskiy

et al. 2018

Adv Elect Materials

201

132

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and environment. [12][13][14] The current industrial and safety standards require blocking of more than 99% of the EM radiation from any electronic devices. [1,[15][16][17] From the other side, the operation of the electronic devices can be disrupted by the outside EM waves. The heat and EM radiation have an inherent connection-absorption of EM waves by any material results in its heating. The energy from EM wave transfers to electrons and then to phonons-quanta of crystal lattice vibrations. The conventional approach for handling the heat and EM radiation problems is based on utilization of the thermal interface materials (TIM), which can spread the heat, and electromagnetic interference (EMI) shielding materials, which can protect from EM waves. These two types of materials have different, and, often, opposite characteristics, e.g., excellent EMI material can be a poor heat conductor, while efficient TIM can utilize electrically nonconductive fillers, resulting in its transparency for EM waves. Here, we propose a concept of the "dual-functional" EMI shielding-TIM materials, and demonstrate it on the example of graphene composites.It is well known that EMI shielding requires interaction of the EM waves with the charge carriers inside the material so that EM radiation is reflected or absorbed. For this reason, the EMI shielding material must be electrically conductive or contain electrically conductive fillers, although a high electrical conductivity is not required. The bulk electrical resistivity on the order of 1 Ω cm is sufficient for most of EMI shielding applications. [1,3,15] Most of the polymer-based materials widely used as TIMs in electronic packaging are electrically insulating and, therefore, transmit EM waves. Conventionally, metal particles are added as fillers in high volume fractions to the base polymer matrix in order to increase the electrical conductivity and prevent EM wave propagation from the device to the environment and vice versa. [1,[18][19][20][21] However, the polymer-metal composites suffer from high weight, cost, and corrosion, which make them an undesirable choice for the state-of-the-art downscaled electronics. Several studies reported the use of carbon fibers, [22][23][24][25][26][27][28][29] carbon black, [30,31] bulk graphite, [32][33][34] carbon nanotubes (CNT), [16,17,[35][36][37][38][39] reduced graphene oxide (rGO), [2,6,[40][41][42][43][44][45][46][47][48][49][50] graphene, [51][52][53][54] and combination of carbon allotropes with orThe synthesis and characterization of epoxy-based composites with few-layer graphene fillers, which are capable of dual-functional applications, are reported. It is found that composites with certain types of few-layer graphene fillers reveal an efficient total electromagnetic interference shielding, SE tot ≈ 45 dB, in the important X-band frequency range, f = 8.2 −12.4 GHz, while simultaneously providing high thermal conductivity, K ≈ 8 W m −1 K −1 , which is a factor of ×35 larger than that of the base matrix material. The efficiency of the d...

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Low percolation threshold and electromagnetic shielding effectiveness of nano-structured carbon based ethylene methyl acrylate nanocomposites

Cited by 143 publications

References 101 publications

Improved dielectric permittivity and retained low loss in layer-structured films via controlling interfaces

Improved dielectric permittivity and retained low loss in layer-structured films via controlling interfaces

Mechanically robust conductive carbon clusters confined ethylene methyl acrylate–based flexible composites for superior shielding effectiveness

Dual‐Functional Graphene Composites for Electromagnetic Shielding and Thermal Management

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