1. Assay of weathering effects on protective polymer coatings using positron annihilation spectroscopy
- Author
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S. Wallace, Cs. Szeles, Ann Schaub, Jun Xu, J. Pfau, Lester D. Hulett, Kelvin G. Lynn, and Bent Nielsen
- Subjects
chemistry.chemical_classification ,Materials science ,General Physics and Astronomy ,Surfaces and Interfaces ,General Chemistry ,Polymer ,Radiation ,Condensed Matter Physics ,Accelerated aging ,Surfaces, Coatings and Films ,Positron annihilation spectroscopy ,Positron ,Nuclear magnetic resonance ,chemistry ,Annihilation radiation ,Composite material ,Spectroscopy ,Doppler broadening - Abstract
Polymer coatings, both with and without pigments, have been subjected to solar radiation and water spray weathering. The degrees of penetration of the weathering effects have been measured by injecting positrons of varying energy, i.e. to variable depths, into the films and observing the Doppler broadening of the annihilation radiation. The method is capable of detecting changes due to weathering effects at very early stages, long before visual examination reveals degradation. As little as one week of exposure caused measurable changes in the polymer structure, which were reflected in the Doppler broadening. Given further development, positron spectroscopy could possibly become a useful complement to the other methods of determining weatherabilities of protective polymer coatings.
- Published
- 1995
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