Visible Light Initiating System for Free Radical Promoted Cationic Polymerization

摘要

A new visible light free radical promoted cation in chain polymerization isreported. The system is based on electron transfer photoreduction of xanthene dye triplets by aromatic amines possessing a hydrogen on the alpha carbon atom to the nitrogen. Subsequent deprotonation of the amine radical cation followed by onium salt oxidation leads to formation of an (alpha-amino carbenium ion and the latter initiates polymerization. Critical to the success of the system is the basicity of the amine, the oxidation potential of the onium salt, and the presence or absence of nucleophilic centers in the monomer to be polymerized. The scope and details of the system are discussed in the publication.