Hydrolytic Caprolactam Polymerization - Progress in Dynamic Simulation

The modeling of hydrolytic caprolactam polymerization is reviewed and a state-of-the-art mathematical model is proposed. The model includes the basic reactions of reversible ring-opening, polyaddition, and polycondensation as well as the reversible formation/hydrolysis and polyaddition of cyclic oligomers. For the first time, a method is proposed to implement stabilization with acids of any functionality so that their impact on the molecular weight distribution can be analyzed. A comparison of the model predictions with experimental data taken from the literature reveals excellent agreement. As shown in this work, the proposed model for the synthesis of polyamide 6 can be used to dynamically compute the complete molecular weight distribution. Therefore, it gives access to desired product designs for this industrially important polymer. The method presented for modeling multichain hydrolysis may also be of interest for other polycondensation systems that result in star-shaped polymers.