Dielectric spectroscopic analysis of degradation in ethylene-propylene-diene copolymer

Daomin Min, Shengtao Li, Naoshi Hirai, Yoshimichi Ohki

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


Gamma-ray induced changes occurring in ethylene-propylene-diene copolymer (EPDM) were analyzed through its complex permittivity spectra. First, four different processes, namely, instantaneous polarization, hopping of ions, segmental relaxation, and dc conduction are found to contribute to the complex permittivity. By fitting the spectra to theoretical equations, it has become clear that the instantaneous polarization and ionic hopping become active by the irradiation, indicating that generation of oxidative products and mobile ions and occurrence of chain scission are induced by gamma rays. Furthermore, since both the thermal expansion and the contribution of the segmental relaxation to the permittivity become less with an increase in dose, it is assumed that crosslinking is induced by the gamma irradiation.

Original languageEnglish
Article number7823416
Pages (from-to)3620-3630
Number of pages11
JournalIEEE Transactions on Dielectrics and Electrical Insulation
Issue number6
Publication statusPublished - 2016 Dec


  • Degradation
  • EPDM
  • dielectric property
  • gamma irradiation

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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