Initiation mechanisms of an anionic ring‐opening polymerization of lactam‐12

A novel liquid system has been developed to initiate the anionic polymerization of lactam‐12. This system, containing both an activator and a catalyst, has the primary advantage over previous systems of permitting infinite storage of the reactant, and it avoids premixing of batches. The anionic species of the system were identified with matrix‐assisted laser desorption/ionization time‐of‐flight measurements, and Fourier transform infrared was used to measure the change in their concentrations during the polymerization. A guanidine anion was formed, and the system initiated the polymerization by this guanidine and by the catalyst. The kinetics of the anionic polymerization of lactam‐12 into polyamide‐12 were followed with differential scanning calorimetry measurements. The determined reaction rates indicated that this liquid system was particularly well suited for initiating in situ polymerization during liquid molding. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3406–3415, 2002