Excerpted from reports ORNL-4842 (Oak Ridge National Laboratory) and MRC-DA-323 (Monsanto Research Corp.). Available from National Technical Information Service, U.S. Department of Commerce, Springfield, Virginia 22151. A portion of this material was presented at the Second Cairo Solid State Conference, Recent Advances in the Science and Technology of Materials, Vol. 2, A. Bishay, Ed., Plenum, New York, 1974, p. 29.
Identification of the active species in the suppression of postirradiation conductivity in polystyrene films for dosimeter application†
Article first published online: 9 MAR 2003
Copyright © 1979 John Wiley & Sons, Inc.
Journal of Applied Polymer Science
Volume 23, Issue 10, pages 3033–3039, 15 May 1979
How to Cite
Kelly, M. J., Parkinson, W. W. and Salyer, I. O. (1979), Identification of the active species in the suppression of postirradiation conductivity in polystyrene films for dosimeter application. J. Appl. Polym. Sci., 23: 3033–3039. doi: 10.1002/app.1979.070231022
- Issue published online: 9 MAR 2003
- Article first published online: 9 MAR 2003
- Manuscript Received: 15 MAY 1978
The resistivity of insulating materials for electrostatic, ion chamber dosimeters must be very high and must remain so after exposure to ionizing radiation. Low dielectric polarization and good fabrication characteristics make hydrocarbon polymers most suitable, but both the conductivity during irradiation and its decay afterward vary greatly even for the same type of polymer, probably depending on impurities. Amorphous, styrene-based polymers and copolymers polymerized in aqueous emulsion and initiated with K2S2O8 were found to have much more rapid decay of conductivity after irradiation than pure polystyrene or other nonpolar polymers. The synthesis method incorporates sulfate groups on the polymer chain ends and leaves emulsifier residues distributed throughout the polymer as was demonstrated by various analytical procedures. To identify the trapping species a synthesis program was carried out varying selected ingredients in the polymerization recipe. It was found that the postirradiation conductivity was not dependent on the chemical nature of the emulsifier residues. On the other hand, the decay time of conductivity after irradiation did depend on the polar groups incorporated in the polymer chain. It was concluded that effective charge carrier traps were constituted of a polar second phase highly dispersed through the polymer by association with polar groups incorporated on the polymer chain.