Degradation of poly(vinyl chloride) films by X-ray radiation
β Scribed by Maria Esther Sbampato; Y. Kawano
- Publisher
- Elsevier Science
- Year
- 1985
- Tongue
- English
- Weight
- 496 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0014-3057
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β¦ Synopsis
The X-ray degradation of pure poly(vinyl chloride) films has been investigated by both i.r. and u.v./visible absorption spectroscopy. The transparent films become slightly yellow during irradiation, i.r. Spectra show changes in relative intensities and band position, particularly in the C-CI stretching region indicating the occurrence of dehydrochlorination and changes in the structure and conformation of the degraded polymer, u.v./Visible spectra of irradiated films show several bands associated with dyenes, carbonyl and many different polyenes and polyenyl radicals. The number of bands increases in the spectra of irradiated samples stored for a long time in air, indicating post-irradiation changes. This effect suggests the formation of polyenyl radicals during irradiation and their subsequent reaction. At the same time, reaction of these radicals with atmospheric oxygen is expected forming C------O groups.
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A~traet--The mechanism of the light-induced degradation of solid poly(vinyl chloride) (PVC) has been investigated, and an overall reaction scheme has been developed, based on values of the quantum yields for the primary photoproducts. Only a very small fraction (0.2%) of the excited polyenes induces
Radiation effects on the formation of conjugated double bonds in the thermal degradation of poly(vinyl chloride) (PVC) and poly(vinyl alcohol) (PVA) were investigated. Thin films of PVC and PVA were either irradiated with β₯-rays at ambient temperature (pre-irradiation) and then subjected to thermal