The radical solution copolymerization of hexafluoropropylene, chlorotrifluoroethylene (CTFE), vinylidene fluoride, and tert-butyl-alpha-trifluoromethylacrylate with different monomers bearing isocyanato groups such as allyl isocyanate, 3-isopropenyl-alpha,alpha'-dimethylbenzyl isocyanate (m-TMI), and 2-isocyanatoethyl methacrylate, initiated by 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane were studied Several of these radical copolymenzations were not successful in contrast to that of CTFE with m-TMI, although m-TMI monomer does not homopolymerize under radical initiation. The resulting poly(CTFE-co-m-TMI) copolymers were characterized by H-1 and F-19 nuclear magnetic resonance and Fourier transform infrared spectroscopy and their compositions assessed by elemental analysis The reactivity ratios of both comonomers were determined by linearization methods of Fineman-Ross, Kelen-Tudos for low conversions of monomers, and by the extended Kelen-Tudos method for high monomer conversions The average values of the monomer reactivity ratios, r(CTFE) and r(m-TMI), were 0 076 and 0 034 at 130 degrees C, respectively, depending on these monomer conversions and the applied methods of calculation. In all cases, r(CTFE) x r(m-TMI) product was close to zero, which indicates that poly(CTFE-co-m-TMI) copolymers exhibit a high tendency toward alternation This was also confirmed by the Igarashi's theory which revealed a high content of CTFE-m-MTI heterodyads. The Q and e values for m-TMI monomer were also assessed (Q(m.TMI) = 0.007 and e(m.TMI) = 0 99) As well as this kinetics of copolymerization, several properties of the obtained fluorofunctional copolymers such as molecular weights (ranging from 1500 to 8200 g mol(-1)), molecular weight distributions (from 1 2 to 2 1) were also investigated Their thermal properties revealed satisfactory thermal stability (higher than 250 degrees C) (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A Polym Chem 48. 2681-2697, 2010