Assessment of Different Application Grades of Post-Consumer\nRecycled (PCR) Polyolefins from Material Recovery Facilities (MRFs)\nin the United States

The recycling of plastics has been\ngaining traction in the following\nyears as many companies, organizations, and governments are pushing\ntoward a more circular economy. However, plastic recycling rates are\nstill small compared to those of plastic production, especially for\npolyolefins, such as high-density polyethylene (HDPE) and polypropylene\n(PP). With the goal of finding applications for recycled plastic resin,\nrecyclers can face some challenges associated with the heterogeneity\nin the polymer properties of plastic waste streams, which could hinder\nthe full potential of recycling due to the lack of a consistent feedstock.\nThis study assessed how an additional sorting step of recycled HDPE\nand PP streams, separating them into two categories based on the previous\napplication, impacts the recycled polymer properties, such as physical,\nmolecular, and thermal. It was demonstrated that manually separating\nHDPE articles previously processed by extrusion blow molding (EBM)\nor injection molding (IM) and PP articles by thermoforming (TF) or\nIM could yield recycled resins with more consistent properties, considering\nthe significant differences between them. This highlights that an\nadditional sorting step would allow recyclers to target more premium\nor currently unattainable plastic processing applications with postconsumer\nrecycled (PCR) resins, which could significantly promote an increase\nin plastic recycling rates. Nevertheless, the development of new technologies\nis needed to automate this extra sorting step, as with the increase\nin scale manual sortation could not be feasible and cost-effective,\nreducing the attractiveness of using PCR resins in comparison to virgin\nones.