Doctoral Dissertations

Keywords and Phrases

Dielectric breakdown

Abstract

"Dielectric materials that are capable of efficiently storing large amounts of electrical energy are desirable for many electronic and power devices. Since the electrical energy density in a dielectric material is limited to εVb²/2, where ε is the dielectric permittivity of the material and Vb is the breakdown strength, increased permittivity and breakdown strength are required for large energy storage density. Interfacial effects can influence the dielectric properties, especially dielectric breakdown resistance in polymer-particle nanocomposites. Several functional organophosphates were used to modify the surface of titania and barium titanate nanofiller particles in order to achieve covalent interface when interacted with polymer and to study the influence the electronic nature of filler surfaces on dielectric properties, in particular the breakdown resistance. Surface modified powders were analyzed by thermogravimetric analysis (TGA) and by X-ray photoelectron spectroscopy (XPS). The dielectric composite films obtained by incorporating surface modified powders in epoxy thermosetting polymer were analyzed by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), impedance spectroscopy, and dielectric breakdown strength measurements. At 30 vol-% filler concentration, a calculated energy density of ~8 J/cm³ was observed for titania based composites and ~8.3 J/cm³ for barium titanate based composites involving electron scavenging interface with minimal dielectric losses compared to pure polymer. Covalent interface composites yielded energy density of ~7.5 J/cm³ for barium titanate based composites at 30 vol.-%. The data indicate that improved dispersion, breakdown strengths and energy densities resulted when electron-poor functional groups were located at the particle surfaces even compared to covalent interface"--Abstract, page iv.

Advisor(s)

Schuman, Thomas P.

Committee Member(s)

Winiarz, Jeffrey G.
Nath, Manashi
Chandrashekhara, K.
Dogan, Fatih

Department(s)

Chemistry

Degree Name

Ph. D. in Chemistry

Sponsor(s)

National Science Foundation (U.S.)

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2011

Journal article titles appearing in thesis/dissertation

  • Improved dielectric breakdown strength of covalently-bonded interface polymer-particle nanocomposites
  • Covalent interface composite breakdown strength
  • Dielectric properties of interface controlled polymer nanocomposites
  • Interface controlled high energy density polymer nanocomposites
  • Influence of electronic nature of filler surfaces on dielectric properties of polymer-particle nanocomposites
  • Electron donating nature of filler surfaces for high energy density polymer-particle nanodielectrics

Pagination

xii, 160 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2011 Sasidhar Veeranjaneyulu Siddabattuni, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

Barium compoundsDielectricsNanocomposites (Materials)Polymeric compositesSurfaces (Technology)

Thesis Number

T 9784

Print OCLC #

775787288

Electronic OCLC #

733075733

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Chemistry Commons

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