Multiblock Copolymers for Recycling Polyethylene-Poly(ethylene terephthalate) Mixed Waste

Keiichiro Nomura, Xiayu Peng, Hanim Kim, Kailong Jin, Hee Joong Kim, Abigail F. Bratton, Christopher R. Bond, Amelia E. Broman, Kevin M. Miller, Christopher J. Ellison

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Plastic pollution is one of the most pressing global environmental issues we face today, in part due to the continued rise in production and use of disposable plastic products. Polyolefins and polyesters are two of the most prevalent polymers in the world accounting for ∼80% of total nonfiber plastic production. Recycling, despite being intrinsically environmentally friendly and sometimes economically viable, remains at a surprisingly low level (<9% in the U.S.) with most plastic waste ending up in landfills. One reason for this low rate of recycling stems from the challenge of recycling mixed waste streams and multicomponent plastics. In mixed waste streams, physical presorting of components prior to recycling requires significant effort, which translates to added cost. For multicomponent plastics (e.g., multilayer films such as food wrappers), the individual plastic components cannot be efficiently physically separated, and they are immiscible with poor interfacial adhesion when melt reprocessed. Thus, direct recycling of mixed plastics by melt reprocessing results in products that lack desired end-use properties. In this study, we describe the synthesis of novel poly(ethylene terephthalate)-polyethylene multiblock copolymers (PET-PE MBCPs) and evaluate their utility as adhesive tie layers in multilayer films and compatibilizer additives for melt reprocessed blends. PET and PE are targeted because they are two of the most prevalent commercial polymers in the world and are high volume waste streams. The work described here demonstrates two key findings. First, the PET-PE MBCPs serve as effective adhesive tie layers between neat PET/PE films with adhesive strength comparable to that of commercially available adhesives. Second, PET/PE (80/20 wt %) blends containing ∼0.5 wt % PET-PE MBCP were melt mixed to mimic recycling mixed plastic waste, and they were found to exhibit mechanical properties better than neat PET. Overall, this study demonstrates that PET-PE MBCPs could significantly enhance the ability to recycle PET/PE mixed waste streams by serving the role as both an adhesive promoting layer and a compatibilizer additive.

Original languageEnglish (US)
Pages (from-to)9726-9735
Number of pages10
JournalACS Applied Materials and Interfaces
Volume12
Issue number8
DOIs
StatePublished - Feb 26 2020

Bibliographical note

Funding Information:
We thank Han Xiao for assistance in SEM. This work was supported by the NSF Center for Sustainable Polymers, CHE-1901635. This research was also partially supported by the University of Minnesota Industrial Partnership for Research in Interfacial and Materials Engineering (IPRIME) through Toray’s membership and their participation in the Industrial Fellows Program. Parts of this work were performed at the University of Minnesota College of Science and Engineering Characterization Facility, which receives partial support from NSF through the MRSEC program. The Table of Contents graphic is created by John Beumer with the NSF Center for Sustainable Polymers.

Publisher Copyright:
Copyright © 2020 American Chemical Society.

Keywords

  • adhesive
  • compatibilizer
  • multiblock copolymer
  • multilayer
  • poly(ethylene terephthalate)
  • polyethylene
  • polymer blends
  • recycling

How much support was provided by MRSEC?

  • Shared

Reporting period for MRSEC

  • Period 6

PubMed: MeSH publication types

  • Journal Article

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