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An Investigation of Stable Free Radicals in Polyimides Using EPR Spectroscopy

Published online by Cambridge University Press:  15 February 2011

Myong K. Ahn ,
Thomas C. Stringfellow ,
Jianming Lei ,
Kenneth J. Bowles  and
Michael Meador
Myong K. Ahn
Affiliation:
Department of Chemistry, Indiana State University, Terre Haute, Indiana 47809
Thomas C. Stringfellow
Affiliation:
Department of Chemistry, Indiana State University, Terre Haute, Indiana 47809
Jianming Lei
Affiliation:
Department of Chemistry, Indiana State University, Terre Haute, Indiana 47809
Kenneth J. Bowles
Affiliation:
NASA Lewis Research Center, Cleveland, Ohio 44135
Michael Meador
Affiliation:
NASA Lewis Research Center, Cleveland, Ohio 44135
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Abstract

Polyimide resins are used as matrix materials in fiber reinforced composites. Such composites are lightweight, have relatively high strength, and can be used at temperatures above 300°C. Postcured PMR-15 produces room temperature electron paramagnetic resonance (epr) spectra from stable free radical species formed during the postcuring stages. The variable temperature EPR spectral intensities indicate the presence of at least two free radical species. The thermo-oxidative degradation involves free radicals generated during the postcuring process in the presence of oxygen gas. These and other recent results including ENDOR and HYSCORE work are discussed.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 305: Symposium I – High-Performance Polymers and Polymer Matrix Composites , 1993 , 217
Copyright
Copyright © Materials Research Society 1993

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References

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