Possible mechanisms of superior resistance of polyamide nanocomposites to partial discharges and plasmas

Norikazu Fuse*, Yoshimichi Ohki, Masahiro Kozako, Toshikatsu Tanaka

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

90 Citations (Scopus)


Degradation profiles induced by partial discharges and those induced by oxygen plasmas are compared for polyamide/mica nanocomposites. Both the resistances to partial discharges and to plasmas improve with an increase in nanofiller content. On the other hand, the partial discharge resistance is not improved if μm-sized glass fibers are added to polyamide. In order to investigate these phenomena, the superior resistance mechanism of nanocomposites is discussed, focusing on the effects of the nanofillers on the bulk and surface structures of the resin. It was revealed from X-ray diffraction and permittivity measurements that the nanofiller loading increases crystallinity of the resin and restricts the molecular motion. This should enhance the resistance to degradation. Furthermore, observation results by scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction revealed that the nanofillers had piled up themselves to form a layered structure on the sample surface in an early stage of degradation. Such a structure acts as a barrier against impact of charged particles and diffusion of gases such as oxygen, which should contribute to the improvement of resistance to degradation as its direct effect and also as its indirect effect by suppressing the oxidation of resin. Moreover, it was also revealed from scanning electron microscopy that the nanofillers impede the growth of surface cavities by partial discharges drastically.

Original languageEnglish
Pages (from-to)161-169
Number of pages9
JournalIEEE Transactions on Dielectrics and Electrical Insulation
Issue number1
Publication statusPublished - 2008 Feb


  • Partial discharge degradation
  • Plasma degradation
  • Polyamide
  • Polymer nanocomposites

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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