Methallylic monomers bearing triethyl or 4-diazabicyclo[2.2.2]octane (DABCO) ammonium side-groups are prepared and copolymerized with chlorotrifluoroethylene (CTFE). First, three different monomers are synthesized from chloro-2-methylprop-1-ene or 3-chloro-2-chloromethylprop-1-ene in fair to good yields (57-95%). Then, several parameters (initiators, aqueous or solution processes, temperature) of the radical copolymerization of these monomers with chlorotrifluoroethylene are investigated. Various initiators are tested in the presence of ammonium perfluorooctanoate (APFO) as water-soluble surfactant, and tert-butyl peroxypivalate/APFO leads to the best results in a mixed solvent (H2O/CH3CN/C4F5H5). In all experiments, the radical copolymerization shows that CTFE is more reactive than the methallylic monomer as evidenced by the characterization of poly(CTFE-co-M) copolymer by nuclear magnetic resonance spectroscopy and elemental analysis. Thermal degradation of these copolymers by thermogravimetric analyses indicates that the copolymers are stable up to 180 degrees C without any degradation and have a T-d,T-10% above 300 degrees C. Finally, their ionic exchange capacities range between 0.94 and 1.69 meq g(-1). (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1721-1729