Résumé
The radical solution copolymerization of hexafluoropropylene, chlorotrifluoroethylene (CTFE), vinylidene fluoride, and tert-butyl-a-trifluoromethylacrylate with different monomers bearing isocyanato groups such as allyl isocyanate, 3-isopropenyl- a,a0-dimethylbenzyl isocyanate (m-TMI), and 2- isocyanatoethyl methacrylate, initiated by 2,5-bis(tert-butylperoxy)- 2,5-dimethylhexane were studied. Several of these radical copolymerizations 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-TMI) copolymers were characterized by 1H and 19F nuclear magnetic esonance 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-Tudo s for low conversions of monomers, and by the extended Kelen-Tudos method for high monomer conversions. The average values of the monomer reactivity ratios, rCTFE and rm-TMI, were 0.076 and 0.034 at 130 C, respectively, depending on these monomer conversions and the applied methods of calculation. In all cases, rCTFE rm-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 (Qm-TMI ¼ 0.007 and em-TMI ¼ 0.99). As well as this kinetics of opolymerization, several properties of the obtained fluorofunctional copolymers such as molecular weights (ranging from 1500 to 8200 g mol1), molecular weight distributions (from 1.2 to 2.1) were also investigated.