Natural nanozeolite as desiccant and reinforcement additive in recycled polymer blends from post-consumer flexible packaging

This study concerned with the upgrading of a mixed polyolefin material, obtained by the sorting and mechanical recycling of flexible packaging of small size (< 0.125 m2). It is mainly composed of polyethylene and a minor amount of polypropylene, with traces of polar contaminants. These latter are responsible for material’s hygroscopicity, which negatively affects its processability and final performances. In the present work, the recyclate was melt compounded with different amounts of a nanometric natural zeolite by means of a single-screw extruder. The idea was to take advantage of the potential double function of this additive, as desiccant and reinforcement. The neat recyclate and its blends with the nanozeolite were extruded in the form of ribbons that were submitted to tensile mechanical tests. Significant increases of both stiffness and strain at break were observed for the systems Fil-s/nanozeolite compared to the neat recyclate, due to an efficient drying and reinforcement action of the selected nanozeolite, despite the non-optimal dispersion of the nanofiller