Photo-oxidation of polymers—II: The sensitized decomposition of hydroperoxides as the main path for initiation of the photo-oxidation of polystyrene irradiated at 253.7 nm
✍ Scribed by G. Geuskens; D. Baeyens-Volant; G. Delaunois; Q. Lu Vinh; W. Piret; C. David
- Publisher
- Elsevier Science
- Year
- 1978
- Tongue
- English
- Weight
- 400 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0014-3057
No coin nor oath required. For personal study only.
✦ Synopsis
Decrease of the intensity of excimer fluorescence during the photo-oxidation of polystyrene indicates that energy transfer occurs from excited phenyl chromophores to oxidation products. Among these, hydroperoxide groups are prominent because, after acting as energy acceptors, they decompose efficiently into free radicals which initiate the photo-oxidation. This effect is clearly demonstrated using cumene hydroperoxide as a model compound for polystyrene hydroperoxides. It is concluded that the sensitized decomposition of hydroperoxide groups provides a general explanation for the characteristic kinetic behaviour of polymers in photo-oxidation as opposed to autoxidation.
R6sum6--La diminution de l'intensit6 de fluorescence d'excim6re au cours de la photo-oxydation du polystyrene indique qu'un transfert d'6nergie a lieu des chromophores ph6nyles excit6s ~t des produits d'oxydation. Parmi ceux-ci, les groupes hydroperoxydes jouent un r61e pr6pond6rant car apr6s s'&re comport6s comme accepteurs d'6nergie ils se d6composent efficacement en radicaux libres qui initient la photo-oxydation. Ceci est clairement d6montr6 en utilisant l'hydroperoxyde de cum6ne comme compos6 mod61e des hydroperoxydes du polystyr6ne. On conclut que la d&omposition sensibilis6e des groupes hydroperoxydes fournit une explication g6n6rale du comportement cin6tique caract6ristique des polym&es dans la photo-oxydation par opposition ~t l'autoxydation.