ABSTRACT:The cationic ring-opening polymerization of azetidine, N-alkylazetidines and a number of azetidines carrying a second functional group is reviewed. Some of these monomers lead to "living" polymers. The rate constants for the polymerization of different azetidines are discussed and compared with the rate constants for the polymerization of other four-membered heterocycles. The nucleophilic ring-opening polymerization of azetidinium salts is discussed. A new polymer with azetidinium endgroups is described. The synthesis, chemical properties, and applications of a number of polymers with pendant azetidinium substituents are described.

No abstract

Trans-esterification of methyl acrylate or methyl methacrylate with I-alkyl-3-azetidinols leads to the corresponding azetidinyl acrylates or methacrylates. These new monomers are polymerized by a free radical mechanism to polymers containing pendant azetidine functions. When these polymers are treated with a mineral acid or with a strong alkylating agent, such as dimethyl sulfate, water-soluble polymers are obtained. An alternative route is to transform the monomer into the azetidinium salt form and to polymerize this salt in aqueous solution. Azetidinium ion containing polymers are stable at room temperature but cross-link to insoluble materials above 120°C.