Atom transfer radical polymerization regeneration

Singh N, Chen Z, Tomer N, Wickramasinghe SR, Soice N, Husson SM. Modification of regenerated cellulose ultrafiltration membranes by surface-initiated atom transfer radical polymerization. J Membr Sci 2008 311(1—2) 225-34. 

Jakubowski W, Matyjaszewski K. Activators regenerated by electron transfer for atom-transfer radical polymerization of (meth)acrylates and related block copolymers. Angew Chem 2006 118 4594 598. 

Elsen, A.M., Butdynska, J., Park, S., Matyjaszewski, K. Activators regenerated by electron transfer atom transfer radical polymerization in miniemulsion with 50 ppm of copper catalyst. ACS Macro. Lett. 2(9), 822-825 (2013)... 

Aliphatic sulfides can be efficient co-initiators for the photoinduced polymerization induced by benzophenone [185, 186]. An exceptionally strong effect was observed for 2,4,6-trimethyl-1,3,5-trithiane (TMT). A model reaction for free-radical formation during photoreduction of an initiator triplet state by a sulfide is the photoreduction of benzophenone by dimethyl sulfide [171, 187-189]. In this process it was established that electron transfer from the sulfur atom to the triplet state of the benzophenone is a primary photochemical step. In this step, radical ions are formed. The overall quantum yields of photoproducts (ketyl radicals and radical anions) are low (Ed) 0.26) in aqueous solution, in the range 0.16-0.20 in mixed water-acetonitrile solution and less then 0.01 in pure acetonitrile. These results suggest that, in organic solvents, back electron transfer within the radical-ion pair to regenerate the reactants is the dominant process. 

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