Rheokinetics of ε-caprolactam anionic-ring polymerization applied to the rapid production of thermoplastic composites

Abstract

The present study focuses on the synthesis and structural analysis of poly-ε-caproamide (PA6), produced through anionic polymerization of ε-caprolactam in bulk, utilizing mono and bifunctional activators. The research investigates the physical properties of PA6 synthesized under various polymerization conditions, aiming to understand how these conditions influence the polymer's behavior. The polymerization kinetics were monitored via dynamic rheology, offering insights into the progression of ε-caprolactam's conversion into PA6. Microstructural changes in the PA6 samples, including variations in the degree of crystallinity and the formation of α and γ crystalline structures, were systematically studied. These transformations were dependent on both the type and concentration of the activator used, as well as the specific polymerization parameters applied. The interplay between these factors significantly impacted the resulting chemical and physical structure of the PA6 samples. In the latter part of the study, hybrid composites were fabricated by reinforcing poly-ε-caproamide with two distinct types of fiber fabrics by reactive processing, achieving a 25% weight fraction of reinforcement. Scanning electron microscopy (SEM) revealed excellent interfacial adhesion between the fibers and the polymer matrix, confirming the effectiveness of the fabrication process and the potential of these composites for advanced material applications.