Thermal stability of electron-irradiated poly(tetrafluoroethylene) - X-ray photoelectron and mass spectroscopic studyPolytetrafluoroethylene (PTFE) was subjected to 3 keV electron bombardment and then heated in vacuum to 300 C. The behavior of the material as a function of radiation dose and temperature was studied by X-ray photoelectron spectroscopy (XPS) of the surface and mass spectroscopy of the species evolved. Lightly damaged material heated to 300 C evolved saturated fluorocarbon species, whereas unsaturated fluorocarbon species were evolved from heavily damaged material. After heating the heavily damaged material, those features in the XPS spectrum that were associated with damage diminished, giving the appearance that the radiation damage had annealed. The observations were interpreted by incorporating mass transport of severed chain fragments and thermal decomposition of severely damaged material into the branched and cross-linked network model of irradiated PTFE. The apparent annealing of the radiation damage was due to covering of the network by saturated fragments that easily diffused through the decomposed material to the surface region upon heating.
Document ID
19910054619
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Wheeler, Donald R. (NASA Lewis Research Center Cleveland, OH, United States)
Pepper, Stephen V. (NASA Lewis Research Center Cleveland, OH, United States)