EFFECT OF PRESSURE AND TEMPERATURE ON TIME-DEPENDENT CHANGES IN GRAPHITE/EPOXY COMPOSITES BELOW THE GLASS TRANSITION.

Jovan Mijovic, Dep of Chemical Engineering Polytechnic Inst of New York, R. C. Liang

Research output: Contribution to journalArticle

Abstract

In the reported experiments, the effects of pressure and temperature on time-dependent changes in physical/mechanical properties of graphite/epoxy composites were investigated. Samples were cut from the eight-ply-thick laminates of commercially used composites, post-cured, and then quenched to environments of various temperature and pressure. Time-dependent changes in their properties were analyzed by thermal and thermomechanical (dynamic mechanical) measurements. An increase in the glass-transition temperature was found to occur as a function of time. The rate of this process was enhanced by an increase in temperature and/or a decrease in pressure. An explanation was offered in terms of types and mechanisms of molecular events that occur in the glassy state. Time-dependent decrease in free volume (and enthalpy) takes place but is not the sole mechanism responsible for the observed increase in T//g. After a certain period of time (which depends on T and P of the environment), additional crosslinking appears to take place.

Original languageEnglish (US)
Pages (from-to)57-66
Number of pages10
JournalPolymer Engineering and Science
Volume24
Issue number1
StatePublished - Jan 1984

Fingerprint

Graphite epoxy composites
Glass transition
Free volume
Crosslinking
Temperature
Laminates
Enthalpy
Mechanical properties
Composite materials
Experiments

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Chemistry
  • Polymers and Plastics

Cite this

EFFECT OF PRESSURE AND TEMPERATURE ON TIME-DEPENDENT CHANGES IN GRAPHITE/EPOXY COMPOSITES BELOW THE GLASS TRANSITION. / Mijovic, Jovan; Polytechnic Inst of New York, Dep of Chemical Engineering; Liang, R. C.

In: Polymer Engineering and Science, Vol. 24, No. 1, 01.1984, p. 57-66.

Research output: Contribution to journalArticle

Mijovic, Jovan ; Polytechnic Inst of New York, Dep of Chemical Engineering ; Liang, R. C. / EFFECT OF PRESSURE AND TEMPERATURE ON TIME-DEPENDENT CHANGES IN GRAPHITE/EPOXY COMPOSITES BELOW THE GLASS TRANSITION. In: Polymer Engineering and Science. 1984 ; Vol. 24, No. 1. pp. 57-66.
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