Post‐Consumer Mechanical Recycling of Thermally Degraded Glass‐Fiber Reinforced Polyamide 6,6 for Electrical Applications

ABSTRACT This study investigates post‐consumer mechanical recycling of a glass‐fiber reinforced polyamide 6,6 for electrical applications (PA66‐GF25, brominated flame‐retardant), using accelerated thermal ageing (180°C, 400 h) to simulate long‐term thermo‐oxidative degradation. Five material states are compared: virgin, aged, recycled‐unaged (post‐industrial analogue), recycled‐aged (post‐consumer analogue), and a 50 wt.% dilution of recycled‐aged with virgin material. Mechanical characterization demonstrates that ageing primarily induces matrix embrittlement, reducing tensile strain at maximum stress from 4.19% to 2.50% while preserving tensile strength (81.5 to 82.7 MPa). Conversely, recycling predominantly compromises reinforcement efficiency through fiber attrition, with mean fiber length decreasing by 42%, resulting in a tensile strength reduction to 51.0 MPa for unaged recyclates. The post‐consumer analogue exhibits cumulative degradation, yielding the lowest flexural strength (83.2 MPa compared to 112.4 MPa for virgin material). However, 50% dilution effectively restores flexural strength (112.1 MPa). Despite mechanical penalties, critical safety properties remain unaffected: all configurations maintain a GWFI of 960°C and a UL94 V‐0 rating, while tracking resistance (CTI 400 V), lost during ageing, is fully recovered upon reprocessing. The results indicate that post‐consumer recycling is feasible, with dilution as an effective route to restore performance while incorporating post‐consumer content.