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A Comparison of Electrical Breakdown Characteristics of Composite Materials Prepared With Unmodified Micro and Nano Scale Barium Titanate

A Comparison of Electrical Breakdown Characteristics of Composite Materials Prepared With Unmodified Micro and Nano Scale Barium Titanate
A Comparison of Electrical Breakdown Characteristics of Composite Materials Prepared With Unmodified Micro and Nano Scale Barium Titanate
High permittivity polymer matrix composites (PMCs) have been widely researched, especially in the field of microelectronics. For this study, high permittivity materials were investigated for their potential to form part of a multi-layer electric field detector. The two main requirements for such composites were high permittivity and a dielectric strength comparable to most standard polymers used as dielectric materials.

Polystyrene was selected as a host polymer due to its high dielectric strength and amorphous structure. Barium titanate, a ferroelectric ceramic from the perovskite family, was selected as a high permittivity filler. Polymer permittivity in PMCs is usually orders of magnitude lower compared to the filler permittivity, although the resultant permittivity of the composite is generally markedly lower than the permittivity of the filler may suggest. This is because very little energy is stored in the ceramic filler, such that any increase in composite permittivity is due to an increase in the average field with the polymer matrix.[1]

Micro and nano scale barium titanate was blended into polystyrene in an effort to discern the initial differences between composites prepared with the two different filler types. It was found that the micro scale barium titanate was well dispersed and from studying SEM micrographs, appeared to have a good particle size distribution. The nanoscale barium titanate was found to be very poorly dispersed in polystyrene, with a wide particle size distributions formed of weakly bound aggregations and some seemingly chemically bonded agglomerations which were regular in shape with a surface texture which was indicative of tightly bound primary particles. Consistent with the differences in particle dispersion within the micro and nano composites, there was a marked difference in AC breakdown strength between the different materials. All electrical breakdown data was analysed using a 2 parameter Weibull distribution. Figure 1 compares the ? values for the micro and nano composites at different filler loadings.
Holt, A F
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Vaughan, A S
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Lewin, P L
78b4fc49-1cb3-4db9-ba90-3ae70c0f639e
Holt, A F
6a6195df-03d6-4174-a504-8ca2965e52df
Vaughan, A S
6d813b66-17f9-4864-9763-25a6d659d8a3
Lewin, P L
78b4fc49-1cb3-4db9-ba90-3ae70c0f639e

Holt, A F, Vaughan, A S and Lewin, P L (2014) A Comparison of Electrical Breakdown Characteristics of Composite Materials Prepared With Unmodified Micro and Nano Scale Barium Titanate. UHVNet 2014, Guildford, United Kingdom. 15 - 16 Jan 2014.

Record type: Conference or Workshop Item (Paper)

Abstract

High permittivity polymer matrix composites (PMCs) have been widely researched, especially in the field of microelectronics. For this study, high permittivity materials were investigated for their potential to form part of a multi-layer electric field detector. The two main requirements for such composites were high permittivity and a dielectric strength comparable to most standard polymers used as dielectric materials.

Polystyrene was selected as a host polymer due to its high dielectric strength and amorphous structure. Barium titanate, a ferroelectric ceramic from the perovskite family, was selected as a high permittivity filler. Polymer permittivity in PMCs is usually orders of magnitude lower compared to the filler permittivity, although the resultant permittivity of the composite is generally markedly lower than the permittivity of the filler may suggest. This is because very little energy is stored in the ceramic filler, such that any increase in composite permittivity is due to an increase in the average field with the polymer matrix.[1]

Micro and nano scale barium titanate was blended into polystyrene in an effort to discern the initial differences between composites prepared with the two different filler types. It was found that the micro scale barium titanate was well dispersed and from studying SEM micrographs, appeared to have a good particle size distribution. The nanoscale barium titanate was found to be very poorly dispersed in polystyrene, with a wide particle size distributions formed of weakly bound aggregations and some seemingly chemically bonded agglomerations which were regular in shape with a surface texture which was indicative of tightly bound primary particles. Consistent with the differences in particle dispersion within the micro and nano composites, there was a marked difference in AC breakdown strength between the different materials. All electrical breakdown data was analysed using a 2 parameter Weibull distribution. Figure 1 compares the ? values for the micro and nano composites at different filler loadings.

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More information

Published date: 15 January 2014
Venue - Dates: UHVNet 2014, Guildford, United Kingdom, 2014-01-15 - 2014-01-16
Organisations: EEE

Identifiers

Local EPrints ID: 366665
URI: http://eprints.soton.ac.uk/id/eprint/366665
PURE UUID: abd7d016-1c61-4a2e-a5ec-a0f730739c08
ORCID for A S Vaughan: ORCID iD orcid.org/0000-0002-0535-513X

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Date deposited: 04 Jul 2014 14:58
Last modified: 11 Jul 2020 00:27

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