Photo-induced metal-free ATRP of MMA with 2,7-bi-(N-penothiazinyl)fluorenone as photocatalyst

In this study, 2,7-bi-(N-penothiazinyl)fluorenone was employed as photocatalyst (PC), ethyl α-bromophenylacetate (EBP) as atom transfer radical polymerization (ATRP) initiator, and photo-induced metal-free ATRP of methyl methacrylate (MMA) was performed at 25°C under blue light irradiation. PMMAs with well-defined architectures and precisely controlled chain lengths were synthsized. The kinetics results confirmed that molecular weights increased linearly with monomer consumption. The molecular weight distributions (M_w/M_n) of the resultant PMMA were narrow. The polymerization was activated and deactivated by periodic light control process. ¹H nuclear magnetic resonance spectrometer (NMR) and gel permeation chromatography (GPC) were used to characterize the obtained PMMAs. The living characters of the polymerization system were further confirmed by chain extension of from the PMMA-Br macroinitiator.