Synthesis of poly(alkoxyamine)s and regeneration of macrocyclic alkoxyxamine by depolymerization

Recently, a great attention has been paid on polymers with dynamic covalent bonding nature because their structures and properties can be changed and tuned after polymerization. In this study, the authors report the synthesis of a polymer with alkoxyamine-based dynamic covalent bonds and its depolymerization behavior. The poly(alkoxyamine) was synthesized by two methods. One is ring-crossover polymerization of an macrocyclic alkoxyamine (1) and the other is polycondensation of alkoxyamine-based diol and dicarboxylic acid dichloride. The depolymerization of the polymer obtained by either way was conducted in 0.65wt % anisole solution at 398 K for 24 h. After heating, GPC profiles, TLC analysis, and FAB-MS measurement of the reaction mixture confirmed that the generated major product is 1. The monomer percentage of depolymerization of the polymer (2) obtained by ring-crossover polymerization is higher than that of the polymer (3) by polycondensation because 2 is structurally ordered polymer. These findings revealed that both 2 and 3 depolymerized to the monomers principally by the intramolecular radical exchange process under high-dilution conditions, the monomer percentage depends on the method of polymer synthesis.