Objective: The short review summarizes old and more recent findings highlighting special features
of polymerizations of heterocyclic monomers, which usually are not observed in processes leading to low molar
mass products. These features include: Influence of the initial monomer concentration on its equilibrium
concentration, role of monomer in determination of the relative reactivity of “free” ions and ion-pairs in propagation,
formation of products composed of linear and cyclic macromolecules, and influence of stereospecificity
of each propagation step on microstructure of the final polymer.
Discussion: In polymerization of heterocyclic monomers elementary reactions responsible for synthesis of
polymers are, in principle, the same as those in “classical” chemistry of heterocyclic small molecules. However,
these two classes of processes are distinct, because in the majority of polymerization systems the same
heteroorganic groups are present in substrates (monomers) and reaction products (linear polymers).
Results: In result, the active polymerization centers react not only with monomers but also with polymers.
Moreover, in polymerization processes the monomer always constitutes a significant part of the liquid medium
and influences its physicochemical properties.