Preparation and various characteristics of epoxy/alumina nanocomposites

Masahiro Kozako, Yoshimichi Ohki, Masanori Kohtoh, Shigemitsu Okabe, Toshikatsu Tanaka

    Research output: Contribution to journalArticle

    18 Citations (Scopus)

    Abstract

    Epoxy/ alumina nanocomposites were newly prepared by dispersing 3, 5, 7, and 10 weight (wt) % boehmite alumina nanofillers in a bisphenol-A epoxy resin using a special two-stage direct mixing method. It was confirmed by scanning electron microscopy imaging that the nanofillers were homogeneously dispersed in the epoxy matrix. Dielectric, mechanical, and thermal properties were investigated. It was elucidated that nanofillers affects various characteristics of epoxy resins, when they are nanostructrued. Such nano-effects we obtained are summarized as follows. Partial discharge resistance increases as the filler content increases; e.g. 7 wt% nanofiller content creates a 60 % decrease in depth of PD-caused erosion. Weibull analysis shows that short-time electrical treeing breakdown time is prolonged to 265 % by 5 wt% addition of nanofillers. But there was more data scatter in nanocomposites than in pure epoxy. Permittivity tends to increase from 3.7 to 4.0 by 5 wt% nanofiller addition as opposed to what was newly found in the recent past. Glass transition temperature remains unchanged as 109°C. Mechanical properties such as flexural strength and flexural modulus increase; e.g. flexural strength and flexural modulus are improved by 5 % and 8 % with 5 wt% content, respectively. Excess addition causes a reverse effect. It is concluded from permittivity and glass transition temperature characteristics that interfacial bonding seems to be more or less weak in the nanocomposite specimens prepared this time, even though mechanical strengths increase. There is a possibility that the nanocomposites specimens will be improved in interfacial quality.

    Original languageEnglish
    Pages (from-to)1121-1127
    Number of pages7
    JournalIEEJ Transactions on Fundamentals and Materials
    Volume126
    Issue number11
    DOIs
    Publication statusPublished - 2006

    Fingerprint

    Nanocomposites
    Alumina
    Epoxy resins
    Bending strength
    Permittivity
    Mechanical properties
    Partial discharges
    Dielectric properties
    Strength of materials
    Fillers
    Erosion
    Thermodynamic properties
    Imaging techniques
    Scanning electron microscopy
    Glass transition temperature

    Keywords

    • Alumina
    • Electrical insulation
    • Epoxy resin
    • Nano-dielectric
    • Nanocomposite
    • Polymer nanocomposite

    ASJC Scopus subject areas

    • Electrical and Electronic Engineering

    Cite this

    Preparation and various characteristics of epoxy/alumina nanocomposites. / Kozako, Masahiro; Ohki, Yoshimichi; Kohtoh, Masanori; Okabe, Shigemitsu; Tanaka, Toshikatsu.

    In: IEEJ Transactions on Fundamentals and Materials, Vol. 126, No. 11, 2006, p. 1121-1127.

    Research output: Contribution to journalArticle

    Kozako, Masahiro ; Ohki, Yoshimichi ; Kohtoh, Masanori ; Okabe, Shigemitsu ; Tanaka, Toshikatsu. / Preparation and various characteristics of epoxy/alumina nanocomposites. In: IEEJ Transactions on Fundamentals and Materials. 2006 ; Vol. 126, No. 11. pp. 1121-1127.
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    abstract = "Epoxy/ alumina nanocomposites were newly prepared by dispersing 3, 5, 7, and 10 weight (wt) {\%} boehmite alumina nanofillers in a bisphenol-A epoxy resin using a special two-stage direct mixing method. It was confirmed by scanning electron microscopy imaging that the nanofillers were homogeneously dispersed in the epoxy matrix. Dielectric, mechanical, and thermal properties were investigated. It was elucidated that nanofillers affects various characteristics of epoxy resins, when they are nanostructrued. Such nano-effects we obtained are summarized as follows. Partial discharge resistance increases as the filler content increases; e.g. 7 wt{\%} nanofiller content creates a 60 {\%} decrease in depth of PD-caused erosion. Weibull analysis shows that short-time electrical treeing breakdown time is prolonged to 265 {\%} by 5 wt{\%} addition of nanofillers. But there was more data scatter in nanocomposites than in pure epoxy. Permittivity tends to increase from 3.7 to 4.0 by 5 wt{\%} nanofiller addition as opposed to what was newly found in the recent past. Glass transition temperature remains unchanged as 109°C. Mechanical properties such as flexural strength and flexural modulus increase; e.g. flexural strength and flexural modulus are improved by 5 {\%} and 8 {\%} with 5 wt{\%} content, respectively. Excess addition causes a reverse effect. It is concluded from permittivity and glass transition temperature characteristics that interfacial bonding seems to be more or less weak in the nanocomposite specimens prepared this time, even though mechanical strengths increase. There is a possibility that the nanocomposites specimens will be improved in interfacial quality.",
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