Glass transition characteristics of poly(aryl ether ketone ketone) and its copolymers

R. K. Krishnaswamy, D. S. Kalika

Research output: Contribution to journalArticlepeer-review

65 Scopus citations


The glass transition characteristics of poly(aryl ether ketone ketone) (PEKK) have been investigated as a function of backbone structure and crystallization history; PEKK 100/0 homopolymer and PEKK 70/30 and 60/40 copolymers were examined, where the numbers represent the terephthalic/isophthalic (T/I) ratio. For the all-para-connected homopolymer, the presence of crystallinity had a significant influence on the calorimetric glass transition properties of the amorphous phase: Tg was offset by as much as 20°C in the crystallized amples as compared to the wholly amorphous material, and a sizeable (WRAP ∼ 0.30) rigid-amorphous-phase fraction was observed. In the copolymers, crystallinity had only a very minor effect on Tg. The rigid-amorphous-phase fraction in the copolymer samples was smaller as compared to the homopolymer, and was negligible (WRAP → 0) for samples prepared under less-restrictive crystallization conditions. Dielectric studies indicated progressive mobilization of the rigid-amorphous-phase fraction above Tg or the copolymer samples, with full mobilization of the on-crystalline fraction observed for those samples crystallized at the highest temperatures. These results show that the introduction of 1,3-connected isophthalate moieties in the PEKK copolymers has a disrupting influence on the persistence of crystalline constraint into the amorphous phase. Similar observations have been reported for poly(phenylene sulfide) copolymers and thermoplastic polyimides that incorporate meta-phenylene linkages in the chain backbone.

Original languageEnglish
Pages (from-to)1915-1923
Number of pages9
Issue number10
StatePublished - May 1996


  • Dielectric relaxation
  • Glass transition
  • Poly(ether ketone ketone)

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry


Dive into the research topics of 'Glass transition characteristics of poly(aryl ether ketone ketone) and its copolymers'. Together they form a unique fingerprint.

Cite this