The role of solvent polarity and cocatalyst structure in the cationic polymerization of 3,3-bis(chloromethyl) oxetane

In the cationic polymerization of 3,3-bis(chloromethyl)oxetane induced by BF₃ the solvent polarity (toluene, methylene chloride, ethylene chloride, nitrobenzene, and nitromethane) does not influence the k_tr/k_p ratio, where k_tr stands for the rate constant of chain transfer to polymer. Increase of the overall polymerization rate is due mainly to the increase of k_i. The application of the steady-state conditions in which the slow formation of the active centers is compensated by the unimolecular chain transfer to polymer allowed the determination of k_tr/k_p ratios for several chain-transfer agents of low molecular weight. Alcohols and ethers of different basicities were used. It was established that the k_tr/k_p ratio is a linear function of ?pK_a of the chain-transfer agents.