Upcycling automotive shredder residue into sustainable hybrid composite materials: a cost-effective solution for circular economy

Automotive shredder residue (ASR), the non-metallic fraction generated during end-of-life vehicle processing, remains a recycling challenge due to its complex composition and limited valorisation pathways. This study presents an approach for transforming 100% non-metallic ASR into hybrid composite panels using recovered plastic fractions as a self-bonding matrix and remaining components as reinforcement. Composite panels were fabricated by hot-press moulding using particle-size distributions and evaluated for mechanical, physical, thermal, and environmental properties. Reducing particle size increased flexural strength from 9.8 MPa to 15.4 MPa, while veneer lamination increased it to 43.2 MPa. The composites exhibited low water absorption (2.46% after 24 h), limited thickness swelling (3.7%), thermal stability to 470 °C, UL 94 HB-compliant flame propagation rate (12.45–13.86 mm/min), and negligible heavy-metal leaching. Life cycle assessment showed lower environmental impacts than commercial MDF and melamine boards. Improved flame performance could enable ASR hybrid panels in light structures.