Physical Aging in Graphite Epoxy Composites.

Abstract

Matrix-dominated mechanical behavior of a graphite/epoxy composite has been found to be affected by sub-Tg annealing. Postcured (+ or -45 deg)4s specimens of Thornel 300 graphite/Narmco 5208 epoxy were quenched from above Tg and given a sub-Tg annealing at 140 deg C for times up to l0(exp 5) min. The ultimate tensile strength, strain-to-break, and toughness of the composite material were found to decrease as functions of sub-Tg annealing time. No weight loss was observed during the sub-Tg annealing. The time-dependent change in mechanical behavior is explained on the basis of free-volume changes that are related to the physical aging of the nonequilibrium glassy network-epoxy. The results imply possible changes in composite properties with service time. jg p3

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Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1981
Accession Number
ADA302998

Entities

People

  • Eric S. Kong
  • Howard G. Nelson
  • Susanna M. Lee

Organizations

  • National Aeronautics and Space Administration

Tags

Communities of Interest

  • Advanced Electronics
  • Weapons Technologies

DTIC Thesaurus Topics

  • Composite Materials
  • Epoxy Composites
  • Epoxy Laminates
  • Glycidyl Ether
  • Graphitic Materials
  • Laminates
  • Materials
  • Materials Testing
  • Mechanical Properties
  • Modulus Of Elasticity
  • Polymers
  • Resins
  • Stress Strain Relations
  • Stresses
  • Tensile Properties
  • Tensile Strength
  • Tensile Testing

Fields of Study

  • Materials science
  • Physics

Readers

  • Materials Science and Engineering.
  • Polymer Science and Engineering.
  • Reinforced Composite Materials