Hydroperoxide groups energy transfer

Polymer "moiety"-polymer "moiety" reactions. Chemical groups formed on the backbone of polymer chains such as peroxy radicals, hydroperoxides, ketones, etc. can undergo bimolecular reactions such as disproportionation, energy transfer, etc. The effect of the polymeric medium apparently is to reduce the bimolecular rates by a factor of about 10 4 relative to fluid solution rates, due to the reduced mobility of both reactants. 

A third mechanism of sensitization involves the formation of an excited state of a ketone by absorption of light followed by energy transfer to a hydroperoxy group and subsequent decomposition of the hydroperoxide. In complex polymer systems it is possible that all three of these mechanisms play an important role. 

The differenee between the donor ionization energy and the acceptor eleetron affinity is a decisive criterion for the exciplex formation. If this difference is too small, ground-state charge transfer (CT) complexes are formed. Electronie energy transfer via exciplexes probably play an important role in the photo-deeomposition of polymer hydroperoxide groups (POOH) sensitized by the carbonyl groups (CO) (cf. section 2.5). 

Energy transfer from the carbonyl (C=0) group to the hydroperoxide (OOH) group. 

This reaction is mainly initiated by an energy transfer process from a carbonyl group (CO) to a hydroperoxide group (OOH) (cf. section 2.5) and is dependent on the cage recombination reaction (cf. section 2.1.3). 

ENERGY TRANSFER FROM THE CARBONYL GROUP TO THE HYDROPEROXIDE GROUP... 

Energy transfer from the excited phenyl group (donor) to the surrounding hydroperoxide groups (acceptors) may occur in many polymers and copolymers containing phenyl groups. 

Phenyl rings absorb incident light at 254 nm and transfer the energy of the excited singlet state to hydroperoxide groups and cause the O—O band dissociation [287, 293]. However, the energy transfer may also occur, to a lesser extent, from the excimer [282]. 

The mechanism of energy transfer depends on the localization of hydroperoxy groups in a polymer matrix. In consequence hydroperoxides can be divided into two groups [284-287, 292, 293] ... 

Between chromophoric groups, e.g. carbonyl (donor) and hydroperoxide (acceptor) groups which participate in the energy transfer process and finally in the generation of free radicals. 

The Energy Transfer Between Carbonyl Groups and Hydroperoxide Structures... 

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