A benign initiating system for cationic polymerization of isobutyl vinyl ether: Silver salt/aryl(alkyl) halide/lewis base

Abstract

Aryl(alkyl) halides and silver salts were studied as environmentally benign initiating systems for cationic polymerization of isobutyl vinyl ether (IBVE). The reactivity of the benzyl cations could be effectively controlled by using dimethyl sulfide (Me2S) as an additive, which was shown to be an effective Lewis base (LB), and diethyl ether as a reaction solvent. Detailed study of various benzyl cations and the order of addition of the reagents revealed that the reaction was controlled by the electronic and steric features of aryl(alkyl) halides, LBs, and IBVE, and a plausible reaction mechanism was presented. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2050–2058

Cationic polymerization of vinyl ethers and p‐methoxystyrene by a benign initiating system: Silver salt/arylmethyl halide/dialkyl sulfide

“…The cationic polymerizations of three VEs using the AgClO 4 /Ph 2 CHBr/dialkyl sulfide initiating system were examined. We have previously shown that IBVE is polymerized cationically in a highly controlled manner in the presence of Me 2 S . In Table , the effect of temperature and sulfides on the polymerization of IBVE is shown.…”

“…The drastic changes in conversion and MWD are attributed to the different coordination ability of these sulfides; the basicity of PhSMe is lower than Me 2 S owing to the resonance effect of phenyl group, and the steric hindrance is another important factor. However, using the similar polymerization conditions (Entry 1), the cationic polymerization of IBVE, a more active monomer than p MOS, proceeded smoothly to reach quantitative conversion in 30 min . These results suggested that the polymerization of more active monomer, VE, was relatively unaffected by the AgClO 4 /BnBr/Me 2 S initiating system.…”

“…The polymerization at 0 °C proceeded in a less controlled manner (Entry 1). As reported, the initiating system containing Me 2 S allowed the polymerization to yield polymers with high M n and narrow MWD at −23 °C (Entry 2), whereas no polymer was obtained at −41 °C (Entry 3) . In contrast, polymers with low M n and broader MWD were obtained in the presence of Et 2 S at −23 °C (Entry 4).…”

“…Poly(VE)s were prepared according to the process described in our previous article . The polymerization procedure for p ‐methoxystyrene was similar to that of the poly(VE)s except that the polymer was recovered by precipitation in methanol and dried under vacuum in this case.…”

“…Recently, we reported that a benign initiating system, AgClO 4 /Ph 2 CHBr/Me 2 S, leads to the living cationic polymerization of IBVE in CH 2 Cl 2 at −23 °C. This initiating system is facile, free from complex catalysts, and easy to operate . In this study, the feasibility of controlled cationic polymerizations of other vinyl monomers such as ethyl vinyl ether (EVE), isopropyl vinyl ether (IPVE), and p ‐methoxystyrene (pMOS), was examined (Scheme ).…”