Mechanical recycling of polyamides: a review

Abstract

This review addresses the importance and challenges of mechanical recycling of polyamides, highlighting its relevance within the global context of the circular economy. It begins by outlining the general characteristics, history, classification, molecular structure, and economic aspects of commercial polyamides. The focus then shifts to the polyamide recycling methods, including chemical and energy recovery, with a focus on mechanical processes, essential for effectively implementing the circular economy by reducing dependence on virgin resources and minimizing environmental impact. The final section summarizes relevant research on the mechanical recycling of polyamides across various industrial sectors. The examples mentioned in the studies here presented demonstrate that polyamides can be successfully recycled from reinforced composites, food packaging, and textiles, underscoring their potential to enhance sustainability while maintaining polymer quality through careful management of moisture content, extrusion cycles, and other parameters. Further research should concentrate on optimizing the separation of polyamides from other materials, minimizing degradation through controlled moisture levels and extrusion cycles, and exploring innovative recycling approaches across diverse applications. Overall, this article provides a comprehensive examination of mechanical recycling for polyamides, bringing studies with new and applicable technologies in this field to promote sustainability and address challenges associated with plastic waste.