Engineering recycled polyethylene infill materials for artificial turf systems: Linking thermal behaviour to system-level performance

Artificial turf systems require sustainable infill materials capable of maintaining adequate functional performance. The aim of this study was to develop recycled polyethylene-based infill materials for artificial turf systems and evaluate the relationship between their thermal behaviour and system-level performance. Recycled polyethylene streams from greenhouse and mulching films were processed through melt compounding using compatibilizers, elastomeric copolymers, mineral fillers, and foaming agents to obtain sustainable infill materials. The resulting blends were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and Melt Flow Rate (MFR) analyses. Laboratory-scale artificial turf systems were evaluated according to FIFA reference procedures, including shock absorption, vertical deformation, ball rebound, and rotational resistance. The results indicated that differences in crystalline structure and chain mobility were accompanied by differences in system-level mechanical behaviour. AF200 blends exhibited lower crystallinity and greater flexibility, achieving values within FIFA reference ranges, whereas AF2000 blends showed higher rigidity and lower overall performance. These findings support the potential of recycled polyethylene as a sustainable alternative to conventional End-of-Life Tires (ELT)-derived rubber infill materials.