Mechanical recycling of cross-linked polyethylene foam scrap wastes – development of a mechanical recycling process and life cycle assessment

Polyethylene boasts a wide array of applications and a substantial contribution to waste generation. This study examines the mechanical recycling of cross-linked polyethylene (XLPE) foams from a technical and ecological perspective. Different approaches for XLPE foam pre-treatment were examined for processability and mechanical and morphological properties. A resulting process flow for mechanical recycling by using the cross-linked foams as filler in a PE regranulate to improve its properties is selected from the approaches. A simplified process approach is developed where different foam types are combined with each other according to a companies’ waste amounts. The approach is also subjected to a life cycle assessment to explore the possible environmental impacts. It was found that some of the foams can be combined in the extrusion process based on similar properties and, depending on the application, lead to improved mechanical properties in a matrix, when used as a filler. Also, environmental impacts can be reduced when a virgin material can substituted to a certain amount. • Mechanical recycling of cross-linked polyethylene (XLPE) foam as a filler • Conducting a crushing process to a screen size of up to 1 mm • Combination of foams to facilitate processing while maintaining almost identical properties • A life cycle assessment of the proposed mechanical recycling approach is performed and highlights the hotspots of the process • Life cycle inventory data is presented for the recycling of crosslinked and expanded foam