Synthesis of highly branched perfluoroethers by direct fluorination,promising new materials based on the hexafluoroacetone–ethylene copolymer

Direct fluorination of the hexafluoroacetone-ethylene copolymer, CH₂CH₂OC(CF₃)₂]_n, under conditions designed to promote fragmentation of the polymer chain has led to the synthesis of a number of structurally unusual branched perfluoropolyethers ? CF₂? CF₂? O-C(CF₃)₂? ]_n. These new perfluoropolyethers have been characterized by ¹⁹F-NMR, and their physical properties are reported. Direct fluorination under milder conditions yields a high-molecular-weight perfluoropolyether.