Influence of Crystallinity on the Dielectric Relaxation Behavior of Poly(ether ether ketone)

Douglass S. Kalika, Rajendra K. Krishnaswamy

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84 Scopus citations


The dielectric relaxation characteristics of amorphous and semicrystalline poly(ether ether ketone) have been investigated as a function of crystallization history; both the glass-rubber (α) relaxation and a sub-glass (β) relaxation were examined. The characteristics of the α relaxation were highly sensitive to crystallinity owing to the constraint imposed on the amorphous phase dipoles by the presence of the crystalline phase. The magnitude of the α relaxation strength indicated an immobilized rigid amorphous phase fraction in the semicrystalline samples which appeared to relax at temperatures above Tg; finite rigid amorphous fractions were observed for both cold-crystallized and melt-crystallized specimens. The sub-glass (β) relaxation was also sensitive to the presence of crystallinity: the isochronal loss maxima measured for the cold-crystallized samples were offset to higher temperatures as compared to the wholly-amorphous material, and a disproportionate decrease in the β relaxation strength with the degree of crystallinity was observed. The influence of the crystalline phase on the β relaxation thus appears to extend well into the amorphous material, suggesting sub-glass motions which encompass a larger segmental length scale as compared to more flexible polymers.

Original languageEnglish
Pages (from-to)4252-4261
Number of pages10
Issue number16
StatePublished - 1993

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry


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