Upcycling End-of-Life Shredded GF/PA6 Waste into High-Performance Hybrid Composites via Novel In-Situ Impregnation

Continuous fibre-reinforced thermoplastic composites are mainly recycled by mechanical recycling, which often results in downcycling due to severe fibre-length attrition during shredding or milling. To address this challenge, the present study investigates two thermomechanical recycling routes for end-of-life (EoL) glass fibre/polyamide 6 composites using compression moulding: (¡) Upcycling via hybridisation, where EoL shredded composites are pelletised and subsequently sandwiched between dry twill glass fibre reinforcements on the two surfaces to produce a hybrid laminate and (¡¡) by direct thermomechanical reprocessing of these composites. Test results revealed that the hybrid laminate displayed a very low void content (<1% by vol.), reflecting effective consolidation during compression moulding. X-ray diffraction (XRD) studies demonstrated the crystalline structures of the laminates. Flexure, tensile tests, and thermomechanical properties obtained via dynamic mechanical analysis (DMA) presented interesting insights into the influence of composite architecture on the mechanical performance of these composites. The hybrid laminate demonstrated the best flexural performance, offering a possible pathway for developing high-performance circular thermoplastic composites for load-bearing applications.