| Abstract |
The issue addressed in this study concerns the hygroscopicity of post-consumer mixed recycled poly-olefins (PCMP). PCMP commonly incorporate polar contaminants, responsible of their moisture sorption and bad smell; as a consequence, it is necessary to dehumidify the recycled material before processing it. This represents a strong technical limitation, since polyolefin converters are not generally equipped with dehumidification plants, so hindering the future circular economy perspectives for these recycled ma-terials. In order to address this issue, in this study we proposed an easy and innovative solution, alter-native to drying and based on the use, never considered before, of zeolites as desiccant additives during PCMP extrusion. At this regard, we prepared, on a pilot scale extrusion plant, several material formu-lations based on undried PCMP loaded with different amounts and types of zeolites, with and without a compatibilizing agent. The obtained systems were submitted to mechanical tensile test to assess the effectiveness and the technological relevance of the proposed strategy with regard to conventional heat drying and a calcium oxide-based desiccant, specially marketed for processing recycled polyolefins. Results showed that the addition of either type of zeolites at 2 wt% loading has an effective desiccant function during PCMP processing and, with respect to heat drying or calcium oxide desiccant, ensures higher strength of the resultant systems (up to ca. 15% and 40%, respectively). Moreover, the use of the compatibilizing agent improves the mechanical performances until they are a little better than those of the heat dried PCMP. Therefore, in a sustainability perspective of the packaging industry, the proposed strategy can offer a tangible contribution to improve the plastic packaging circularity and to reach the EU plastic recycling targets. (c) 2021 Published by Elsevier Ltd. |
