Amorphous orientation and its relationship to processing stages of blended polypropylene/ polyethylene fibers

Amy M. Trottier, J. W. Zwanziger, N. Sanjeeva Murthy

Research output: Contribution to journalArticlepeer-review


Changes in the molecular orientation, melting behavior, and percent crystallinity of the individual components in a fibrous blend of isotactic polypropylene (iPP) and high-density polyethylene (HDPE) that occur during the melt extrusion process were examined using wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). The crystalline orientation of each component was found using Wilchinsky's treatment of uniaxial orientation and described by the Hermans-Stein orientation parameter. The amorphous orientation was found by resolving the X-ray diffraction pattern in steps of the azimuthal angle into its iPP and HDPE crystal-line and amorphous reflections. The utility of DSC and WAXD analyses to capture the effects of small differences in processing, and the use of these results as fingerprints of a particular manufacturing process were demonstrated. Major increases in the melting temperatures, percent crystallinities, and molecular orientations of the iPP and HDPE components occurred during the main stretching stage of the melt extrusion process. The annealing stage was found to have little to no effect on the melting behavior and molecular orientation of these components.

Original languageAmerican English
Pages (from-to)4047-4057
Number of pages11
JournalJournal of Applied Polymer Science
Issue number6
StatePublished - Jun 15 2008
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Surfaces, Coatings and Films
  • Polymers and Plastics
  • Materials Chemistry


  • Amorphous
  • Blends
  • Fibers
  • Orientation
  • X-ray


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