Mechanical recycling of polyamide 6 and polypropylene for automotive applications

Abstract

This study investigates the mechanical recycling of polyamide 6 (PA6) from discarded fishing nets and polypropylene (PP) from automotive battery scraps and household waste for automotive applications. The mechanical properties of both materials were evaluated through tensile, impact, and thermal testing, revealing that recycled PA6 (r‐PA6) and recycled PP (r‐PP) can achieve mechanical performance similar to virgin materials. Recycled PA6 was reinforced with 30% glass fiber (GF), significantly enhancing its tensile strength from 70 to 170 MPa, comparable with virgin PA6's (76 MPa). Furthermore, the tensile modulus of r‐PA6 increased from 7720 to 8500 MPa. Recycled PP was compounded with thermoplastic elastomers (TPE) and fillers, such as calcium carbonate (CaCO₃) and talc, improving its impact strength from 5 to 18 KJ/m2 and improving thermal stability, with a heat deflection temperature (HDT) reaching 95°C. The optimized formulations for r‐PP, particularly from automotive battery scrap, achieved a melt flow index (MFI) of 12–16 g/10 min, preventing molding defects. This study highlights the importance of controlled thermal treatments, appropriate additive use, and accurate processing conditions in producing high‐quality recycled polymer compounds.Highlights Recycled PA6 reinforced with 30% GF achieves a tensile strength of 170 MPa. Thermal treatment increases the tensile modulus of r‐PA6 to 8500 MPa, similar to virgin PA6. Incorporating TPE improves the impact strength of r‐PP to 18 KJ/m2. Calcium carbonate and talc enhance the thermal stability of r‐PP to 95°C. The melt flow index of r‐PP optimized to 12–16 g/10 min for better moldability.