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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.

Currently, plastic packaging represents a global challenge and has become a key point of attention for governments, media and consumers due to the visibility of the waste it generates. Despite their high resource efficiency, the perceived non-recyclability of polymeric films risks precluding them from being a relevant packaging solution in a circular economy approach. In this regard, the aim of this study was to implement a strategy to try closing the loop, via the mechanical recycling of post-consumer flexible packaging of small size (denoted as Fil-s) to obtain new films. In particular, two lots of Fil-s were used, which are PE/PP blends differing for the PP content and the presence of polar contaminants. The suitability for film blowing extrusion of these recycled materials, as such and after the addition of a compatibilizer and/or a lamellar nanosilicate, was evaluated. It was first evidenced that the difficulty of producing blown films with the pristine recycled materials, due to the frequent bubble breakages, occurring even at low draw ratios. Moreover, the shear and extensional rheological behavior of all Fil-s based systems was usefully correlated with their processability features, evidencing the key roles of the nanofiller to stabilize the bubble and of the compatibilizer to ensure a uniform film deformation, avoiding its premature breakage. Even if the adopted upgrading strategies allowed the production of blown films with both types of Fil-s, the different components of the recycled matrices were proven to significantly affect their processability and final film performances.