Abstract
Photochemical reactions occur as a result of activation of a molecule (polymer macromolecule) by light to its excited singlet (S*) and/or triplet (T*) states (cf. section 1.2). Pure degradation (chain scission and/or crosslinking) occurs only in an inert (vacuum, nitrogen or argon) atmosphere. When air (oxygen) is present, photo-oxidative degradation occurs. In the photo-oxidative degradation of almost all polymers the following steps can be considered:
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Initiation step: formation of free radicals.
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Propagation step: reaction of free polymer radicals with oxygen, production of polymer oxy- and peroxy-radicals and secondary polymer radicals, resulting in chain scission.
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3.
Termination step: reaction of different free radicals with each other, resulting in crosslinking.
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© 1995 Springer Science+Business Media Dordrecht
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Rabek, J.F. (1995). Photochemical aspects of degradation of polymers. In: Polymer Photodegradation. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-1274-1_2
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DOI: https://doi.org/10.1007/978-94-011-1274-1_2
Publisher Name: Springer, Dordrecht
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Online ISBN: 978-94-011-1274-1
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