Effects of crystallinity on dielectric properties of poly(L-lactide)

Saki Hikosaka*, Hiroto Ishikawa, Yoshimichi Ohki

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


Poly(L-lactide) is attracting much attention as a biodegradable polymer. In this paper, effects of crystallinity on dielectric properties of PLLA are discussed. At 80 $C, which is above the glass transition temperature (= about 60 °C), the conductivity increases with a decrease in crystallinity. A thermally stimulated polarization current (TSPC) peak, which seems to be due to segmental-mode relaxation, appears in all the samples at temperatures around 65 to 70 °C, and it becomes smaller as the crystallinity increases. All the samples show two thermally stimulated depolarization current (TSDC) peaks at around 65 °C and around 90 to 100 °C. The lower-temperature peak seems to be due to the segmental-mode relaxation, and the other due to the normal-mode relaxation. Moreover, all the samples show a drastic increase in the real part of the complex permittivity (εr′) and a peak in its imaginary part (Ïμr.) at frequencies from 10-1 to 104 Hz, depending on the measurement temperature. The crystallinity dependencies of the two parts are similar to those of the TSPC and TSDC peaks at around 65 to 70 °C. Therefore, the increase in εr′ and the peak in εr″ are ascribable to the segmental-mode relaxation.

Original languageEnglish
Pages (from-to)1-8
Number of pages8
JournalElectronics and Communications in Japan
Issue number7
Publication statusPublished - 2011 Jul 1


  • Biodegradable polymer
  • complex permittivity
  • crystallinity
  • electrical conduction
  • glass transition
  • thermally stimulated current

ASJC Scopus subject areas

  • Signal Processing
  • Physics and Astronomy(all)
  • Computer Networks and Communications
  • Electrical and Electronic Engineering
  • Applied Mathematics


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