The radical copolymerization of vinylidene fluoride (VDF) with 4-bromo-1,1,2-trifluorobut-1-ene (C4Br) was examined. This bromofluorinated alkene was synthesized in three steps, which started with the addition of bromine to chlorotrifluoroethylene. In contrast to the ethylenation of 1,1-difluoro-1,2-dibromochlorethane, which failed, that of 2-chloro-1,1,2-trifluoro-1,2-dibromoethane was optimized and led to 2-chloro-1,1,2-trifluoro-1,4-dibromobutane. The kinetics of the copolymerization of VDF with this brominated monomer initiated by t-butyl peroxypivalate led to an assessment of the reactivity ratios, r(VDF) = 0.96 +/- 0.67 and r(C4Br) = 0.09 +/- 0.63, at 50 degreesC. The suspension copolymerization was also carried out, and the chemical modifications of the resulting bromo-containing poly(vinylidene fluoride)s were attempted and consisted mainly of elimination or nucleophilic substitution of the bromine. (C) 2005 Wiley Periodicals, Inc.