A deformation induced order‐disorder transition in isotactic polypropylene

Ravi F. Saraf, Roger S. Porter

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


In this study, isotactic polypropylene (i‐PP) has been deformed by uniaxial compression to draw ratios up to 16×, and at draw temperatures from 30°C to 140°C. An order‐disorder transition in the crystals is observed at draw temperatures well above the stability limit, 70°C, reported for the disordered phase; Furthermore, this disordered phase (called smectic) is found to induce ductility and improve the efficiency of draw. The deformation induced smectic phase has been characterized using WAXS, DSC, and on‐line compression load versus draw ratio measurements. In consequence, a set of process conditions are offered to optimize draw. A mechanism for plastic deformation of i‐PP is also suggested, using the smectic phase as a probe.

Original languageEnglish (US)
Pages (from-to)842-851
Number of pages10
JournalPolymer Engineering & Science
Issue number13
StatePublished - Jul 1988
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Polymers and Plastics
  • Materials Chemistry


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