NMR analysis of the hardening of epoxy resins by piperidine

The hardening of an epoxy resin and a model compound (phenylglycidyl ether) by piperidine with additions of CoCl2, CuCl2 and piperidine trisulphide was investigated by using high resolution NMR. With the reaction of the model compound as an example it is shown that in the course of hardening there are stages of tertiary amine formation and quaternization of the amine. The addition of piperidine leads to a marked change in the reaction mechanism, the process becoming autocatalytic.