Preparation of fluorinated copolymers by copper-mediated living radical polymerization

摘要

Copper-mediated living radical polymerization mediated with pyridine imine ligands has been used for the synthesis of poly(methaerylate)s and polystyrene incorporating fluorinated moieties as either initiators or monomers as well as in the presence of fluorinated solvents. It was found that fluorinated organics do not interfere detrimentally in the polymerization mechanism. alpha-Perfluoroalkyl initiators have been used for the polymerization of MMA initiated by both 2-perfluoroalkyl ethyl 2-bromoisobutyrate (ZONYL BA initiator) and 2-perfluoroalkyl ethyl-co-poly(ethylene glycol) 2-bromoisobutyrate (ZONYL FSO initiator) initiators which occurs at an almost identical rate to that initiated by ethyl 2-bromoisobutyrate (EIBr). The M-n increased linearly with conversion, and the polydispersity indices were low throughout all polymerizations (<1.20). Polymerization of MeOPEG-AU initiated by 2-perfluoroalkyl ethyl 2-bromoisobutyrate (ZONYL BA initiator) at 60 degreesC results in a water-soluble/dispersible polymer with M-n = 6700 g mol(-1) and PDI = 1.07. Perfluoroalkylethyl methacrylate (FEMA) proves difficult to homopolymerize due to solubility problems but has been used to form statistical copolymers with MMA and styrene. Synthesis of AB block copolymers using fluorinated macroinitiators with a methacrylate B block gives both hydrophobic, MMA, and hydrophilic, MeOPEG-MA, polymers with well-defined alpha-terminal block copolymers and PDI as low as 1.10. Copper-mediated living radical polymerization was found to be an effective method for the synthesis of fluorine-containing synthetic polymers. [References: 42]