Spontaneous alternating zwitterion polymerizations

Random copolymerization of different oxazolines is described in Section 15.1,2.2. The reactivity ratios increase as expected with monomer basicity 18). Statistical copolymers of cyclic imino ethers with other groups of monomers are not known, although oxazolines and oxazines form readily alternating copolymers with a number of electrophilic monomers by spontaneous zwitterionic polymerization. The mechanism and examples of this process are discussed in Section 15.2.1. 

The addition of a Lewis acid to a polymerization recipe involving free radical initiators makes possible copolymerizations which would not otherwise occur e.g. Isobutene + methyl acrylate. The copolymerizations may also be unaffected by the addition of inhibitors or transfer reagents. Spontaneous alternating copolymerization may also occur between nucleophilic (Mn) and electrophilic (Mb) monomers through zwitterion intermediates (5) which are capable of propagation (6). 

Zwitterions are the propagating species in a number of spontaneous polymerizations that occur upon mixing electron donor and acceptor monomers. Several reviews of spontaneous polymerizations via zwitterion intermediates are available [317-323]. In this novel type of polymerization reaction there is no need to add an initiator or catalyst. Alternating copolymers have been obtained in some cases when at least one of the monomers contains a heterocycle. In these polymerizations a nucleophilic monomer (Mn) and an electrophilic monomer (Me) react to form a zwitterion [Eq. (89)]. This zwitterion is referred to as a genetic zwitterion. ... 

The zwitterion, which can be isolated, spontaneously polymerizes to an alternating iminoester at 150 C ... 

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