Decay of catalytic activity during the cationic polymerization of capryllactam

At lower concentrations of initiator and temperatures above 200°C, the polymerization of capryllactam initiated by hydrogen chloride is characterized by two kinetically different stages: the initial rapid growth becomes considerably slower due to the fast transformation of the original growth centers into amidines. The steep decrease in molecular weight during hydrazinolysis indicates that the amidine groups are also present inside polymer molecules. The formation of these structures may be explained by condensation of the amino endgroups with the amide or acyllactam groups.