Regularities of cationic polymerization of substituted aziridines

The cationic polymerization of some ordinary N- and C-substituted aziridines, initiated by the methyl etherate of boron trifluoride, shows a typical “temporarily living” character. Kinetic and spectroscopic data on the polymerization of N-methyl-aziridine under conditions under consideration as well as molecular mass characteristics of the polymers obtained, testify to the zwitter-ions as active centres of chain growth. This process is characterized by slow initiation, stationarity of propagation and slow termination with the participation of the polymer chain just after a monomer is used up. Such peculiarity of zwitter-ion polymerization allows to obtain liniar functional polyaziridines of given molecular mass by termination of the system by means of appropriate nucleophilic compounds.