Nanosilicates in Compatibilized Mixed Recycled Polyolefins: Rheological Behavior and Film Production in a Circular Approach

Abstract

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.

Assessment of Melt Compounding with Zeolites as an Effective Deodorization Strategy for Mixed Plastic Wastes and Comparison with Degassing

“…The physical-chemical characterization (DSC, FTIR, etc.) of Fil-S was already extensively conducted in our previous papers [30,[32][33][34], evidencing that its main polymer components are polyethylene (LLDPE and LDPE) and a minor fraction of polypropylene (5%wt) with traces of polar contaminants.…”

“…Regarding the selection of the zeolites, to be effective as adsorbents it is essential to consider their chemical affinity with the substances that should be adsorbed [19][20][21][22][23][24][25][27][28][29]33], as well as the dimensions of these latter with respect to the zeolites' pore size. In particular, it was reported in the literature [19] that excellent adsorbent performances can be obtained if the ratio between the zeolite pore size (D PORE ) and the kinetic molecular diameter of VOCs (D VOC ) is in the range 1.7 < D PORE /D VOC < 3.…”

Investigation of an Upcycling Strategy for Mixed Plastic Wastes from Urban Collection

“…[3] A lot of studies are devoted to improving recycled plastics quality, mainly with the aim to increase the mechanical performance through compatibilization and mineral reinforcement strategies. [4][5][6][7][8][9][10][11][12] However, despite the numerous efforts made so far, the quality of the recycled material is still lacking, making it not attractive for the market as secondary raw material, especially due to poor processability and bad odor.…”