DocumentCode :
886698
Title :
Electron-Radiation Effects on the AC and DC Electrical Properties and Unpaired Electron Densities of Three Aerospace Polymers
Author :
Long, Sheila Ann T. ; Long, Edward R., Jr. ; Ries, Heidi R. ; Harries, Wynford L.
Author_Institution :
National Aeronautics and Space Administration, Langley Research Center, Hampton, VA 23665-5225
Volume :
33
Issue :
6
fYear :
1986
Firstpage :
1390
Lastpage :
1395
Abstract :
The effects of gigarad-level total absorbed doses from 1-MeV electrons on the post-irradiation alternating-current (ac) and direct-current (dc) electrical properties and the unpaired electron densities have been studied for Kapton,® Ultem,® and Mylar.® The unpaired electron densities (determined from electron paramagnetic resonance spectroscopy) and the dc electrical conductivities of the irradiated materials were monitored as functions of time following the exposures to determine their decay characteristics at room temperature. The elevated-temperature ac electrical dissipations of the Ultem and Mylar were affected by the radiation. The dc conductivity of the Kapton increased by five orders of magnitude, while the dc conductivities of the Ultem and Mylar increased by less than an order of magnitude, due to the radiation. The observed radiation-generated changes in the ac electrical dissipations are explained in terms of known radiation-generated changes in the molecular structures of the three materials. A preliminary model relating the dc electrical conductivity and the unpaired electron density in the Kapton is proposed.
Keywords :
Aerospace materials; Composite materials; Conducting materials; Conductivity; Dielectric materials; Dielectrics and electrical insulation; Electrons; Mechanical factors; Polyethylene; Polymers;
fLanguage :
English
Journal_Title :
Nuclear Science, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9499
Type :
jour
DOI :
10.1109/TNS.1986.4334611
Filename :
4334611
Link To Document :
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