Thermal Degradation of Polyamides. Part 1. Aliphatic Polymers.

The thermal degradation of two aliphatic polyamides, polyhexamethylene adipamide nylon 6.6 and polyhexamethylene sebacamide nylon 6.10 have been studied. Molecular weight changes, weight loss, and volatile product analysis were used to help elucidate the reaction mechanisms. The presence of low molecular weight material and polymerizable end groups in these polymers complicated the interpretation of molecular weight changes during degradation. The weight loss data obtained allowed the calculation of rate data. Nylon 6.6 degradation gave an activation energy of 45 kcalmole while nylon 6.10 degradation was characterized by an activation energy of 55 kcalmole. Both polymers gave evidence of random scission kinetics. The volatile products were consistent with the occurrence of further condensation, scission, and cross-linking reactions.