The impact of impurities on the mechanical properties of recycled polyethylene. Issue 4 (23rd December 2020)

• Record Type: Journal Article
• Authors: Thoden van Velzen, Eggo Ulphard; Chu, Sharon; Alvarado Chacon, Fresia; Brouwer, Marieke T.; Molenveld, Karin
• Is Part Of: Packaging technology and science. Volume 34:Issue 4(2021)
• Page Start: 219
• Page End: 228
• Publication Date: 2020-12-23
• Subjects: mechanical properties -- mechanical recycling -- polyethylene bottles -- polymeric composition -- post‐consumer plastic waste; Packaging -- Periodicals; 688.8
• DOI: 10.1002/pts.2551
• Languages: English
• ISSNs: 0894-3214

Abstract

Abstract: The mechanical properties of mechanically recycled polyethylene (rPE) were studied in relation to the composition of the feedstock. This composition varied in six steps from only bottle bodies from a single type of high‐density polyethylene (HDPE) to the complete composition of an industrially sorted polyethylene (PE) product, including other packaging components, other PE‐based packages, sorting faults and residual waste. The rPE with the highest impact resistance was made from the single‐grade bottle bodies. The addition of bodies made from other types of PE already reduced the impact resistance with 11%. All the other stepwise additions of packaging components and faultily sorted objects caused the impact resistance to decrease further. Conversely, the elongation at break grew with the stepwise addition of these packaging components and faultily sorted objects. From the used methods, the best analysis method to accurately determine the polymeric composition of the rPE was found to be near‐infrared‐assisted flake analysis. This method can not only be used to determine the polymeric composition, but due to the strong correlation with the impact resistance, it is also a valuable indicator for the expected mechanical properties of rPE. Abstract : The Charpy impact resistance of recycled polyethylene relates to the concentration of polypropylene in the recycled matrix. The polypropylene originates from packaging components and sorting mistakes.