Proton-Conducting Polymers via Atom Transfer Radical Polymerization of Diisopropyl-p-Vinylbenzyl Phosphonate and 4-Vinylpyridine

Copolymerization of diisopropyl-p-vinylbenzyl phosphonate (DIPVBP) and 4-vinylpyridine (4VP) by atom transfer radical polymerization (ATRP) was studied in the presence of different catalyst systems using DMF as solvent. When a CuIBr complex was used as catalyst and the reaction was carried at 90 °C in DMF, dramatically fast radical termination was observed and the chain propagation was almost stopped at an early stage of ATRP. CuICl with different ligands were used as ATRP catalyst systems to modify the reaction conditions. An improved ATRP catalyst system was CuICl/N,N,N′,N′′,N′′′,N′′′-hexamethyltriethylenetetramine (HMTETA). The 1H NMR technique was successfully applied online to investigate the kinetic parameters of atom transfer radical copolymerization (ATRCP) of DIPVBP and 4VP. The reactivity ratio of DIPVBP (rDIPVBP) and 4VP (r4VP) was 0.69 and 1.17, respectively, which were calculated with the Extended Kelen−Tudos method at high conversions (15−40%). A proton-conducting statistical copolymer (poly(vinylbenzyl phosphonic acid-stat-4VP)) was then obtained by complete hydrolysis of the phosphonate groups.