A "Water Shell" Model for the Dielectric Properties of Hydrated Silica-filled Epoxy Nano-composites

Zou, Chen; Fothergill, J.C.; Rowe, S.

doi:10.1109/icsd.2007.4290834

Cited by 40 publications

(28 citation statements)

References 6 publications

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“…However, it is likely that this "water shell" becomes fragmented away from the particle and some of the water is dispersed into the surrounding polymer [6]. This deduction is confirmed by Fourier transform infrared-multiple internal reflection (FTIR-MIR) spectra by Nguyen [7] and Bowden and Throssell [8].…”

Section: Discussionsupporting

confidence: 58%

The influence of water on dielectric behavior of silica-filled epoxy nano-composites and percolation phenomenon

Zou

Fothergill

et al. 2007

2007 Annual Report - Conference on Electrical Insulation and Dielectric Phenomena

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This is the unspecified version of the paper.This version of the publication may differ from the final published version. Abstract: The dielectric properties of epoxy resin were studied as a function of hydration by dielectric spectroscopy. The dielectric spectroscopy measurements show different conduction and quasi-DC behaviors at very low frequencies (<10 -2 Hz) with activation energies dependent on the hydration. These observations lead to the development of a model in which a "water shell" is formed around the nanoparticles. The multiple shell model, originally proposed by Lewis and developed by Tanaka, has been further developed to explain low frequency dielectric spectroscopy results in which percolation of charge carriers through overlapping water shells was shown to occur. At 100% relative humidity, water is believed to surround the nanoparticles to a depth of approximately 10 monolayers as the first layer. A second layer of water is proposed that is dispersed by sufficiently concentrated to be conductive. If all the water had existed in a single layer surrounding a nanoparticle, this layer would have been approximately 5 nm thick at 100% RH. Filler particles that have surfaces that are functionalized to be hydrophobic considerably reduce the amount of water absorbed in nanocomposites under the same conditions of humidity. PEA results show that the wetted epoxy specimens have a higher threshold field of space charge accumulation than such dry specimens since water enhances charge decay. Permanent repository link

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Section: Discussionsupporting

confidence: 58%

The influence of water on dielectric behavior of silica-filled epoxy nano-composites and percolation phenomenon

Zou

Fothergill

et al. 2007

2007 Annual Report - Conference on Electrical Insulation and Dielectric Phenomena

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“…This behavior is also seen in polymers, but the level of moisture absorbed in polymerceramic nanocomposites is higher compared to pure polymer or polymer filled with micron-sized ceramic particles [15]. It was observed that nanocomposites absorb up to 60% more water than unfilled and polymer filled with micron-sized ceramic particles [16]. The main site of water absorbed in nanocomposites is the interface of the polymer and the ceramic.…”

Section: Introductionmentioning

confidence: 76%

Effects of moisture absorption on the electrical parameters of embedded capacitors with epoxy-BaTiO3 nanocomposite dielectric

Alam

Azarian

Pecht

2012

J Mater Sci: Mater Electron

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In this work the effects of moisture absorption on the electrical parameters of embedded capacitors is investigated. Capacitors of two different areas embedded inside a four-layered printed wiring board were selected for this work. The dielectric was a nanocomposite of epoxy and BaTiO 3 which is common dielectric material used in embedded capacitors. These capacitors were exposed to elevated temperature and humidity conditions (85°C and 85% RH) and two parameters, capacitance and dissipation factor, were measured in situ. The diffusion of moisture in the dielectric was also modeled using the finite element method (FEM), and the changes in electrical parameters were calculated theoretically. The FEM methodology was then verified by applying it on capacitors of different dimensions.

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“…6. The decrease in 'Tg' is due to presence of water nanolayer around the nanoparticle [57], and increase [56] is due to as nanofiller content increases the interparticle distance reduces which increases the overlapping of immobile polymer regions around nanoparticle which will in turn increase 'Tg' [13].…”

Section: Inconsistencies In 'T G ' [56]mentioning

confidence: 99%

A Review on Nanocomposite Based Electrical Insulations

Paramane¹,

Kumar²

2016

Transactions on Electrical and Electronic Materials

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The potential of nanocomposites have been drawing the intention of the researchers from energy storage to electrical insulation applications. Nanocomposites are known to improve dielectric properties, such as the increase in dielectric breakdown strength, suppressing the partial discharge (PD) as well as space charge, and prolonging the treeing, etc. In this review, different theories have been established to explain the reactions at the interaction zone of polymer matrix and nanofiller; the characterization methods of nanocomposites are also presented. Furthermore, the remarkable findings in the fields of epoxy, cross-linked polyethylene (XLPE), polypropylene and polyvinyl chloride (PVC) nanocomposites are reviewed. In this study, it was observed that there is lack of comparison between results of lab scale specimens and actual field aged cables. Also, non-standardization of the preparation methods and processing parameters lead to changes in the polymer structure and its surface degradation. However, on the positive side, recent attempt of 250 kV XLPE nanocomposite HVDC cables in service may deliver a promising performance in the coming years. Moreover, materials such as self-healing polymer nanocomposites may emerge as substitutes to traditional insulations.

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A "Water Shell" Model for the Dielectric Properties of Hydrated Silica-filled Epoxy Nano-composites

Cited by 40 publications

References 6 publications

The influence of water on dielectric behavior of silica-filled epoxy nano-composites and percolation phenomenon

The influence of water on dielectric behavior of silica-filled epoxy nano-composites and percolation phenomenon

Effects of moisture absorption on the electrical parameters of embedded capacitors with epoxy-BaTiO3 nanocomposite dielectric

A Review on Nanocomposite Based Electrical Insulations

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