Studies on Polymerization and Depolymerization of ε-Caprolactam Polymer. IX. Reformation Reaction of ε-Caprolactam from Poly-ε-capramide

The reformation reaction of ε-caprolactam from poly-ε-capramide having modified end-groups has been studied. It was found that no ε-caprolactam was reformed at 230°C from the polymer of which all of the end-groups were –COONa or –NHAc groups, while ε-caprolactam was reformed slowly at 257°C. The rate of the reformation of ε-caprolactam from the polymer having –COONa or –NHAc end-groups is about 1/10 of that from the polymer having normal end-groups at 257°C and it is independent of the polymerization degree of the polymer. The polymerization and the depolymerization reactions of ε-caprolactam polymer occur predominantly on the end-groups and the interchange reaction between two adjacent amide groups in the polymer chain occurs slowly.