Accession Number : ADA303710

Title :   Low-Energy Electron Effects on Tensile Modulus and Infrared Transmission Properties of a Polypyromellitimide Film.

Descriptive Note : Technical memo.,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER

Personal Author(s) : Ferl, James E. ; Long, Edward R., Jr

PDF Url : ADA303710

Report Date : JUN 1981

Pagination or Media Count : 18

Abstract : Infrared (IR) spectroscopy and tensile modulus testing have been used to evaluate the importance of experimental procedure on changes in properties of pyromellitic dianhydride-p,p'-oxydianiline film exposed to electron radiation. The radiation exposures were accelerated, approximate equivalents to the total dose expected for a 30-year mission in geosynchronous Earth orbit. The change in the tensile modulus depended more on the dose rate and the time interval between exposure and testing than on total dose. The IR data varied with both total dose and dose rate. A threshold dose rate existed below which reversible radiation effects on the IR spectra occurred. Above the threshold dose rate, irreversible effects occurred with the appearance of a new band. Postirradiation and in situ IR absorption bands were significantly different in that the latter were much smaller. This difference suggests that the electron radiation induced metastable, excited molecular states. jg p18

Descriptors :   *TENSILE PROPERTIES, *FILMS, *ELECTRONS, *LOW ENERGY, *ELECTRON IRRADIATION, *INFRARED TRANSMITTERS, TIME INTERVALS, INFRARED SPECTROSCOPY, EARTH ORBITS, MOLECULAR STATES, POLYMERS, THRESHOLD EFFECTS, ANHYDRIDES, REVERSIBLE, ABSORPTION SPECTRA, DOSE RATE, BAND SPECTRA, IRREVERSIBLE PROCESSES, IMIDES, ANILINES, RADIATION EFFECTS, RADIATION HAZARDS, SYNCHRONOUS SATELLITES.

Subject Categories : Polymer Chemistry
      Physical Chemistry
      Atomic and Molecular Physics and Spectroscopy
      Nuclear Physics & Elementary Particle Physics
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE