Nitroxide Mediated PhotoPolymerization NMP2: the First Example

New alkoxyamines bearing a chromophore group linked to the aminoxyl function are proposed as new photoiniferters. These original compounds decompose under UV irradiation to generate the corresponding alkyl and nitroxide radicals. Laser Flash Photolysis and ESR experiments showed an efficient shortening of the excited state lifetimes suggesting a C-O bond homolytic dissociation under UV irradiation. When these compounds are used as photoiniferters, a linear growth of the polymer chain, reaching 80 % of conversion in less than 500 s, is observed combined with a re-initiation of the photopolymerization after the end of the irradiation: this is the first report showing a true Nitroxide Mediated PhotoPolymerization NMP2 process.