Drawing Behavior of Ultrahigh Molecular Weight Polyethylene (UHMWPE) Fibers in Supercritical CO2

Abstract

The drawing behavior of Ultrahigh Molecular Weight Polyethylene (UHMWPE) fibers in supercritical CO2 (scCO2) is compared to that in air at different temperatures. Temperature substantially influences the drawing properties in air, while in scCO2 a constant draw stress and tensile strength are observed. Differential Scanning Calorimetry (DSC) shows an apparent development of a hexagonal phase along with significant improvements in crystallinity of air-drawn samples with increasing temperature. The existence of this phase is not confirmed by WIDE ANGLE X-RAY SCATTERING (WAXS) showing that air-drawn samples crystallize in an internally constrained manner. In contrast, scCO2 allows crystals to grow without constraints through a possible crystal-crystal transformation, increasing the processing temperature to 110 deg. C.

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Document Details

Document Type
Technical Report
Publication Date
Nov 01, 2002
Accession Number
ADA408631

Entities

People

  • Alan J. Lesser

Organizations

  • University of Massachusetts Amherst

Tags

Communities of Interest

  • Human Systems

DTIC Thesaurus Topics

  • Contrast
  • Dacron
  • Dielectric Polymers
  • Electron Microscopy
  • High Pressure
  • Materials
  • Mechanical Properties
  • Molecular Weight
  • Physical Properties
  • Polyethylenes
  • Polymers
  • Scattering
  • Stresses
  • Tensile Strength
  • Wide Angles
  • X Ray Scattering
  • X Rays

Fields of Study

  • Materials science

Readers

  • Materials Science and Engineering.
  • Mechanical Engineering/Mechanics of Materials.
  • Reinforced Composite Materials