Anionic Polymerization of ε-Caprolactam under the Influence of Water: 2. Kinetic Model

Abstract

The reaction kinetics of anionic polymerization for the production of anionic polyamide 6 (aPA6) are widely understood. It is also known that this reaction is very sensitive to external influences such as water. This paper analyzes and quantifies the influence of water on the reaction of ε-caprolactam to anionic polyamide 6. A kinetic model is developed in which the reactive molecules of the activator and catalyst are defined as variables and the concentrations of activator and catalyst as well as water content are considered. A model for the calculation of the reaction kinetics is established and validated with experimental data. The developed model can be used to predict the influence and compensation of water by addition of surplus activator and catalyst during the polymerization of ε-caprolactam.

Development and Analysis of an In-Mold Coating Procedure for Thermoplastic Resin Transfer Molding to Produce PA6 Composites with a Multifunctional Surface

“…The poor conversion at the interface and thus the adhesion failure can be explained with the hydrophilic nature of polyamide 6, which blocks the polymerization process in regions close to the surface [19,38]. Our previous measurements show that PA6 prepared by anionic ring-opening polymerization can absorb approximately 0.05% moisture at 50% relative humidity in one hour [39].…”

Efficient polymerization and crystallization kinetics coupling of polyamide 6 synthesis for liquid composite molding process modeling

“…As the model is phenomenological in nature, [ 28 ] with its parameters being determined purely numerically using experimental results, [ 26 ] they are no evident parameters to choose. Recently, Wendel et al [ 38 ] attempted to take humidity into account in a polymerization model for anionically synthetized PA6. They chose to modify parameters and and exponentially relate them to the number of reactive molecules according to time.…”

Isothermal anionic polymerization of ε‐caprolactam to polyamide‐6: Kinetic modeling and application for production process

“…Furthermore, the chemical composition of the reactive mixture consisting of ε‐CL, initiator, and activator, as well as the process temperature strongly influence the reaction kinetics and the polymer characteristics 7–18 . In addition, a deactivating influence of moisture on anionic polymerization is known to occur 19–22 . Also, a high process temperature accelerates the polymerization and at the same time slows down the crystallization while a low process temperature leads to a fast crystallization, which in turn causes a slow polymerization 7,23 …”