Photooxidation free radical aspects

Photooxidation of poly(styrene) has been a subject of considerable interest over the past 25 years (14,15). However, the surface photooxidation of poly(styrene), the aspects of which are most pertinent to the proposed photooxidative scheme, has only been examined recently (16,17). Free radical intermediates have been proposed to account for the formation of oxidized groups upon 254 nm irradiation of poly(styrene). 

In the present ehapter we consider the inter- or intramolecular photoinduced electron transfer phenomenon. We mainly focus on photoinduced electron transfer processes that lead to the photoinitiation of polymerization, and on processes initiated by photoredueed or photooxidized excited states. We concentrate especially on a description of the kinetic schemes, a description of the reactions that follow the primary proeess of eleetron transfer, and the characteristics of intermediates formed after electron transfer. Understanding the complexity of the processes of photo-initiated polymerization requires a thorough analysis of the examples illustrating the meehanistie aspects of the formation of free radicals with the ability to start polymerization. 

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