No Catalyst Copolymerization by Spontaneous Initiation. A New Method of Preparation of Alternating Copolymers

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Abstract
A new type of copolymerization is presented which proceeds without any added catalyst. A monomer of nucleophilic reactivity (MN) is mixed with the second monomer having electrophilic reactivity (ME) to produce a zwitterion +MN—ME-(1), which is responsible for initiation as well as propagation. By the following scheme of reactions, alternating copolymer is formed. Sometimes the reactions between zwitterion species 1, 2, and 3 with free monomer occur, which give rise to the formation of copolymer having a biased composition. Cyclic imino ethers, exoimino cyclic ether, and azetidine have been explored as the MN comonomers. β-Propiolactone, cyclic anhydride, sultone (sulfolactone), acrylic acid, acrylamide, and β-hydroxyethyl acrylate have successfully been adopted as the ME comonomers. Copolymerization occurred without any catalyst with all combinations of MN and ME monomers, and various alternating copolymers were produced. Several important results which explicate the new concept are presented and discussed.