A composition comprises a distribution of telomers of ethylene and at least one fluoroalkyl or perfluoroalkyl halide, the telomers comprising at least one polymethylene segment (—(CH2)n—) and at least one halomethyl group (—CXH2) and optionally comprising at least one non-fluorine heteroatom, and the halogen being selected from iodine and bromine; wherein the distribution has a number average ratio of methylene moieties of the polymethylene segment to the halomethyl groups of at least about 15.