Abstract
Fluorinated copolymers bearing ammonium groups were prepared by radical copolymerization of fluorinated olefins (chlorotrifluoroethylene, hexafluoropropylene) with different vinyl ethers (2-chloroethyl, cyclohexyl, n-butyl, and ethyl vinyl ethers) followed by the cationization of these copolymers with trimethylamine. Copolymers were obtained in high yield (generally >85%), with molecular weights ranging from 8000 to 25 000 g mol-1. From elemental analysis as well as 1H and 19FNMR spectroscopy, the alternating structure of these polymers was confirmed. The chemical modification of these copolymers consisted of a two-step reaction: (i) the replacement of the chlorine atom by an iodine atom followed by (ii) the substitution of the halogen atom by the trimethylamine into a quaternary ammonium. The resulting copolymers were characterized with the usual techniques to assess their compositions and structures. Their thermal analyses, in dynamic mode, under air, showed decomposition temperatures (Td,10%) higher than 200 C. Electrochemical properties of some of these polymers were also studied, showing ionic exchange capacities (IEC) ranging from 0.50 to 0.75 mequiv g-1 (theoretical IEC up to 3.63 mequiv g-1) and water uptake of 13-25%.