Simulation of a Real Recycling Scenario for an HDPE‐Based Packaging

Several factors still limit the achievement of effective mechanical recycling strategies for polyolefins. In particular, the thermomechanical degradation undergone during reprocessing, the different degradation forms experienced during the service life, as well as the cross-contaminations resulting from non-fully accurate sorting technologies, cause the obtainment of recyclates with heterogeneous microstructure, which significantly affect their final properties, often limiting their possible future applications. This study evaluates the combined effects of aging and cross-contamination for high-density polyethylene (HDPE) containing low amounts of polypropylene (PP) and polyethylene terephthalate (PET) as contaminants. HDPE systems were subjected to photo-oxidative or thermo-oxidative treatments and reprocessing to simulate real recycling scenarios. Results show that PP and PET contamination significantly reduce HDPE ductility under thermo-oxidative conditions, while exerting minimal impact on photo-oxidized materials.