Time-temperature-transformation diagram for reactive processing of polyamide 12

In order to describe the different events occurring during the anionic poly merization of polyamide 12 (PA12), a general concept of a time, temperature , and transformation (TTT) diagram was established and related to reactive processing conditions. Polymerization kinetics were established, and it was found that the reaction was best described by an autocatalytic expression. Polymerization temperatures above and below the final polymer melting temp erature were considered. Furthermore, the variation of the melting temperat ure and viscosity were followed as a function of the polymerization time an d degree of conversion. It was shown that monomer-polymer phase separation and crystallization may occur during PA12 polymerization. The results could be adapted for use during liquid molding of PA12 polymers and their compos ites. (C) 2001 John Wiley & Sons, Inc.