Oxygen-tolerant photo-induced metal-free atom transfer radical polymerization

Well-defined poly (methyl methacrylate) (PMMA) was prepared by metal-free atom transfer radical polymerization (metal-free ATRP) using a commercially available inexpensive organic dye fluorescein (FL) as a photocatalyst, and amines as electron donors without degassing of the polymerization mixture. The effect of the molar ratio of the electron donor to FL on the kinetic and induction period during the polymerization was investigated. Moreover, the kinetics of MMA polymerization was affected by the catalyst concentration, electron donor species, and oxygen concentration in the polymerization system. Finally, the high activity of the metal-free ATRP system in the presence of a small amount of oxygen was confirmed by chain extension polymerization.