Abstract
When alkali metal reacts with ε-caprolactam, it was found experimentally that hydrogen and N-alkali metal ε-caprolactam are produced at first. The rate of polymerization of ε-caprolactam in the presence of N-alkali metal derivative was studied. The change in the electric conductivity during polymerization was also measured. In this case the polymerization is expected to proceed by an ionized molecule.