Study of Polymeric Nematic Phases.

Abstract

An experimental determination of the persistence length of an aromatic polyamide-hydrazide, X-500, was undertaken to compare values obtained by light scattering, intrinsic viscosity, and small angle x-ray diffraction. Corrections for molecular weight heterogeneity are well known and should be applied. The status of the treatment excluded volume effects for non-gaussian wormlike chains is not currently adequate. We were unsuccessful in an attempt to obtain experimental values of the entropy changes at the crystal-nematic and nematic-isotropic transitions for a thermotropic nematic polymer. This arose from the difficulty in identifying the nematic phase in highly viscous thermotropic polymers. Investigations of flow instabilities created by an electric field indicates this procedure may furnish a convenient conformatory test for thermotropic nematic phases. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Feb 12, 1981
Accession Number
ADA096032

Entities

People

  • W. R. Krigbaum

Organizations

  • Duke University

Tags

Communities of Interest

  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Chemistry
  • Diffraction
  • Electric Fields
  • Electrodes
  • Enthalpy Changes
  • Hydrazides
  • Instability
  • Light Scattering
  • Macromolecules
  • Magnetic Fields
  • Melting Point
  • Molecular Weight
  • Polymers
  • Scattering
  • Transitions
  • X Rays
  • X-Ray Diffraction

Readers

  • Materials Science and Engineering.
  • Polymer Science and Technology
  • Systems Analysis and Design