Original SF5-Containing Fluorinated Copolymers Based on Vinylidene Fluoride

The radical co- and terpolymerization of fluorinated monomers bearing an SF 5 group, XYC CZSF 5 (where X, Y, and Z represent either H or F atoms) with 1,1-difluoroethylene (vinylidene fluoride, VDF or VF 2 ) and hexafluoropropene (HFP), is presented. Although these SF 5 monomers do not homopolymerize under radical initiation, they do copolymerize (and terpolymerize) in solution, in the presence of radical initiators with VDF (and with VDF and hexafluoropropylene (HFP)), hence leading to original copolymers bearing SF 5 side groups. NMR characterizations and yields enabled one to compare the relative reactivities of F 2 C CFSF 5, HFP, perfluoromethyl vinyl ether, and perfluoropropyl vinyl ether in the copolymerization of VDF with these fluoroolefins. The degree of fluorine substitution on the ethylenic unit of the SF 5 monomers had an influence on their reactivity, on their relative incorporation in the copolymers, and on the molar masses of the resulting terpolymers the higher the fluorine in the SF 5 monomer, the higher molecular weight. Interestingly, the greater the degree of fluorine substitution of the SF 5 -containing monomer, the greater the yield of the reaction. The yield also increased as the amount of initiator was increased. The relative concentrations of the comonomers in each copolymer were assessed by 19 F and 1 H NMR spectroscopy. The thermal properties (thermal stability and glass transition temperature) of these resulting SF 5 -containing fluoropolymers were also examined.