Simultaneous Recycling of PA6 /Carbon Fiber Composite Residues and Ionomer Residues for the Production of PA6 ‐Based Composites: Effect of Processing Route on Properties

ABSTRACT This study investigates the simultaneous recycling of two polymer residues, polyamide 6/carbon fiber (PA6‐CF) composite residues and ionomer residues, to produce new PA6‐based composites. The influence of the processing route is evaluated by comparing direct injection molding with extrusion followed by injection molding. The composites are characterized for morphology, fiber length, thermal behavior, crystallinity, and mechanical properties. The incorporation of PA6‐CF residues increases the tensile and flexural moduli, tensile and flexural strengths, and heat deflection temperature (HDT), even with a low carbon fiber content of 2.25 wt% and despite fiber shortening during reprocessing. However, the impact strength and elongation at break decrease, a behavior commonly reported for short‐fiber‐reinforced systems. Ionomer residue incorporation reduces stiffness, strength, thermal stability, crystallinity, and HDT, but significantly improves ductility and impact strength, with the composites' impact strength exceeding that of neat PA6. SEM micrographs suggest good fiber–matrix interaction and show a homogeneous carbon fiber dispersion. Although prior extrusion slightly enhances tensile and flexural properties, both processing routes ultimately produce composites with similar overall characteristics. These findings suggest that direct injection molding can serve as a viable alternative that simplifies processing and has the potential to reduce energy consumption and costs.