Activation behavior and dielectric relaxation in polyvinyl alcohol and multiwall carbon nanotube composite films

Chakraborty, Goutam; Meikap, Ajit Kumar; Babu, Ramesh; Blau, Werner J.

doi:10.1016/j.ssc.2011.03.013

Cited by 28 publications

(19 citation statements)

References 30 publications

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“…b) shows TGA data of the samples, which were recorded in the temperature range30-800 ºC at a heating rate of 20 ο C/min under N 2 atmosphere. These TGA data reveal that theFe 3 O 4 loading in PVA-Fe 3 O 4 is 20 wt.% with two-step degradation (one at 278 ºC for PVA and one at the onset of 460 ºC for Fe 3 O 4 ) and SLGAPC loading in PVA-SLGAPC was 15 wt% with 2 step degradation (one at 278 ºC for PVA and one at the onset of 340 ºC for FTIR spectrum of I) PVA, II) PVA-Fe 3 O 4 , III) PVA-SLGAPC, IV) PVA-SLGAPCFe 3 O 4 composites FTIR analysis: Figure 4 shows the FTIR spectrum of I) PVA, II) PVA-Fe 3 O 4 , III) PVA-SLGAPC and IV) PVA-SLGAPC-Fe 3 O 4 .…”

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confidence: 99%

Single-layer graphene-assembled 3D porous carbon composites with PVA and Fe₃O₄ nano-fillers: an interface-mediated superior dielectric and EMI shielding performance

Rao

Yadav

Aepuru

et al. 2015

Phys. Chem. Chem. Phys.

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In this study, a novel composite of Fe3O4 nanofiller-decorated single-layer graphene-assembled porous carbon (SLGAPC) with polyvinyl alcohol (PVA) having flexibility and a density of 0.75 g cm(-3) is explored for its dielectric and electromagnetic interference (EMI) response properties. The composite is prepared by the solution casting method and its constituents are optimized as 15 wt% SLGAPC and 20 wt% Fe3O4 through a novel solvent relaxation nuclear magnetic resonance experiment. The PVA-SLGAPC-Fe3O4 composite shows high dielectric permittivity in the range of 1 Hz-10 MHz, enhanced by a factor of 4 as compared to that of the PVA-SLGAPC composite, with a reduced loss by a factor of 2. The temperature dependent dielectric properties reveal the activation energy behaviour with reference to the glass transition temperature (80 °C) of PVA. The dielectric hysteresis with the temperature cycle reveals a remnant polarization. The enhanced dielectric properties are suggested to be the result of improvement in the localized polarization of the integrated interface system (Maxwell-Wagner-Sillars (MWS) polarization) formed by the uniform adsorption of Fe3O4 on the surface of SLGAPC conjugated with PVA. The EMI shielding property of the composite with a low thickness of 0.3 mm in the X-band (8.2-12.4 GHz) shows a very impressive shielding efficiency of ∼15 dB and a specific shielding effectiveness of 20 dB (g cm(-3))(-1), indicating the promising character of this material for flexible EMI shielding applications.

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confidence: 99%

Single-layer graphene-assembled 3D porous carbon composites with PVA and Fe₃O₄ nano-fillers: an interface-mediated superior dielectric and EMI shielding performance

Rao

Yadav

Aepuru

et al. 2015

Phys. Chem. Chem. Phys.

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“…It indicates the presence of one more relaxation mechanism due to the hopping frequency of charge carriers coincides with that of external field [15]. By addition of BSZT in the polymer matrix, more and more free charges may accumulate on the interface resulting in a decrease of relaxation time and thus, the relaxation process shift towards the higher frequencies [16]. …”

Section: Resultsmentioning

confidence: 89%

Dielectric relaxation behavior and electrical conduction mechanism in polymer-ceramic composites based on Sr modified Barium Zirconium Titanate ceramic

et al. 2012

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In this paper, we report the dielectric relaxation behavior and electrical conduction mechanism of Sr modified Barium Zirconium Titanate, (Ba 1-x Sr x Zr 0.1 Ti 0.9 O 3 (x0 0.1, 0.2, 0.3)) (BSZT) ceramic in the polyvinyl alcohol (PVA) matrix. The single phase BSZT ceramics are prepared by the conventional solid state route and are added to the polymer matrix at 25:75 volume percentage. Surface morphology of polymer ceramic composite identifies the uniform distribution of the ceramic particles in the polymer matrix. Dielectric and tangent loss spectrum of the composites indicates the distribution of relaxation time. Electric modulus analysis shows the relaxation peaks of bulk and interface properties, which follows the Arrhenius law. The ac conductivity spectrum of pure PVA obeys Jonchers power law and polymer composites obey the double power law which conduction mechanisms are explained by Jump Relaxation Model. The activation energy varies from the relaxation to conduction mechanism indicates that the different charge contributions are involved in both the processes.

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“…At higher frequencies, the rotational motion of the polar molecules is not sufficiently rapid to attain equilibrium with the external electric field, thus leading to declined dielectric constant . By adding Al particles in the polymer matrix, more and more free charges may accumulate on the interface, thereby resulting in a decrease of relaxation time and thus, the relaxation process shift towards the higher frequencies .…”

Section: Resultsmentioning

confidence: 99%

“…. Large variations in the real and imaginary part of permittivity at low frequencies and high temperatures are minimized in the electric modulus presentation, since electrode polarization, space charge injection, and absorption of impurities can be neglected . Electric modulus is defined as the inverse quantity of complex permittivity:

M * = \frac{1}{ε^{*}} = \frac{ε^{'}}{ε^{' 2} + ε^{″ 2}} + i \frac{ε ″}{ε^{' 2} + ε^{″ 2}} = M^{'} + i M ″

where

ɛ^{'}

M^{'}

, and

ɛ ″

M ″

are the real and imaginary parts of dielectric permittivity and electric modulus, respectively.…”

Section: Resultsmentioning

confidence: 99%

Dielectric studies of al nanoparticle reinforced epoxy resin composites

et al. 2016

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Epoxy (EP) resin based nanocomposites with aluminum (Al) nanoparticles were prepared by solution method, with ultrasonic assisted dispersion followed by hot-pressing methods. The dielectric permittivity, loss tangent, conductivity, and electric modulus of the nanocomposites were investigated by dielectric spectroscopy measurements in a wide frequency range from 1 to 10 7 Hz at temperatures from 2208C to 2008C. For all samples, the dielectric permittivity, dissipation factor, and electric conductivity increase with increasing temperature due to enhanced chain mobility above glass transition temperature (T g ) . Broadband dielectric spectroscopy shows the multiple dielectric processes in the Al/epoxy nanocomposites corresponding to interfacial polarization (IP), a-relaxation, and ionic conductivity, respectively. IP is detected at low frequencies and high temperatures. A primary a-relaxation process is found at near T g at the middle frequencies and the intermediate dipolar effect (IDE) is presented at high frequencies. The mechanisms responsible for dielectric relaxation, conductivity process, and electric modulus response have been discussed in detail.

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Activation behavior and dielectric relaxation in polyvinyl alcohol and multiwall carbon nanotube composite films

Abstract: The dc and ac electrical transport property of Polyvinyl Alcohol-Multiwall Carbon Nanotubes (PVA-MWNT) composites has been investigated within a temperature range

Cited by 28 publications

References 30 publications

Single-layer graphene-assembled 3D porous carbon composites with PVA and Fe₃O₄ nano-fillers: an interface-mediated superior dielectric and EMI shielding performance

Single-layer graphene-assembled 3D porous carbon composites with PVA and Fe₃O₄ nano-fillers: an interface-mediated superior dielectric and EMI shielding performance

Dielectric relaxation behavior and electrical conduction mechanism in polymer-ceramic composites based on Sr modified Barium Zirconium Titanate ceramic

Dielectric studies of al nanoparticle reinforced epoxy resin composites

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Activation behavior and dielectric relaxation in polyvinyl alcohol and multiwall carbon nanotube composite films

Abstract: The dc and ac electrical transport property of Polyvinyl Alcohol-Multiwall Carbon Nanotubes (PVA-MWNT) composites has been investigated within a temperature range

Cited by 28 publications

References 30 publications

Single-layer graphene-assembled 3D porous carbon composites with PVA and Fe3O4 nano-fillers: an interface-mediated superior dielectric and EMI shielding performance

Single-layer graphene-assembled 3D porous carbon composites with PVA and Fe3O4 nano-fillers: an interface-mediated superior dielectric and EMI shielding performance

Dielectric relaxation behavior and electrical conduction mechanism in polymer-ceramic composites based on Sr modified Barium Zirconium Titanate ceramic

Dielectric studies of al nanoparticle reinforced epoxy resin composites

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Product

Resources

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Single-layer graphene-assembled 3D porous carbon composites with PVA and Fe₃O₄ nano-fillers: an interface-mediated superior dielectric and EMI shielding performance

Single-layer graphene-assembled 3D porous carbon composites with PVA and Fe₃O₄ nano-fillers: an interface-mediated superior dielectric and EMI shielding performance