High Pressure X-Ray Studies of Polymers. III. Phase Transformation of Polyethylene.

Abstract

A systematic study was made on polyethylene at high pressures and elevated temperatures using X-ray diffraction. Polyethylene with an initial chain-folded morphology and the orthorhombic crystal structure did not transform to any other phase before melting at temperature and pressure. Crystallization, however, at high pressures producing extended-chain crystals gave rise to either a new crystal phase, probably hexagonal or the orthorhombic phase depending on the crystallization conditions. A reversible solid-state phase transformation was observed between the orthorhombic and hexagonal phases. None of the previous interpretations put forward to account for the high pressure D.T.A. and dilatometric studies of polyethylene, would appear to be appropriate in view of these findings. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Oct 15, 1976
Accession Number
ADA031799

Entities

People

  • B. A. Newman
  • K. D. Pae
  • T. P. Sham

Organizations

  • Rutgers University–New Brunswick

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Barometric Pressure
  • Crystal Structure
  • Crystallization
  • Crystals
  • Dielectric Polymers
  • Diffraction
  • High Pressure
  • Materials
  • Materials Science
  • Melting
  • Melting Point
  • New Jersey
  • Phase Transformations
  • United States
  • Universities
  • X Rays
  • X-Ray Diffraction

Fields of Study

  • Chemistry

Readers

  • Materials Science and Engineering.