THE INFLUENCE OF THE NATURE OF CATALYST U SED IN THE ANIONIC-POLYMERIZATION OF LACTAMS ON THE DEGRADATION OF POLYCAPROAMIDES

We studied kinetics of catalytic reamidation of polycaproamide in N-me thylpyrrolidone at 170-degrees-C. A change in formation rate of NH2-gr oups was found to depend on two competing processes: the reaction of r eamidation (1) and condensation of formed NH2-groups with the imide br anching nodes (2). The rate constants of these reactions were measured to be k1 = 1.34 x 10(-2) l/(mol s) and k2 = 2.6 l/(mol s). High value s of k2 provide an explanation of NH2-groups being absent in anionic-p olymerization-produced polycaproamide. Investigations of the kinetics of reacidylation of polyamide chain revealed that the rate of chain de struction and the final level of the latter are much higher than those in the reamidation reaction and depend substantially on the nature of a catalyst used. Owing to the similar reaction mechanism, the activit y of the reaction centers follows the same sequence with the activity of these centers in polymerization: most active are lactam anions, whi le ion pairs are the least active centers.