Abstract
A persistent perfluoroalkyl radical (PPFR), perfluoro-3-ethyl-2,4-dimethyl-3-pentyl, is shown to be a good source of *CF3 radicals; a useful radical for initiating the polymerization of vinylidene fluoride (VDF). NMR characterizations of the resulting PVDF homopolymers shows that polymerization of VDF was exclusively initiated by *CF3 radicals, as evidenced from the thermal decomposition of PPFR at T > 80 °C. The addition of *CF3 radical onto VDF is regioselective leading to CF3-CH2-CF2-PVDF and the α,-trifluoromethyl groups act as an efficient label to assess the molecular weights of the resulting PVDFs by 19F NMR spectroscopy. No evidence was found about the presence of the initial persistent radical attached onto the macromolecular chains. Various [PPFR]0 / [VDF]0 initial molar ratios lead to CF3-PVDF-CF3 of various molecular weights ranging from 4,100 to 7,500 g.mol-1. When that ratio decreases, both the molecular weights and the thermostability of these original PVDFs polymers increases.