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Upgrading and Enhancement of Recycled Polyethylene Terephthalate with Chain Extenders: In-Depth Material Characterization

Abstract

Chemical chain extenders (CEs) can be used to restore the properties of recycled low-molecular-weight polyethylene terephthalate (PET). The aim of this work is to investigate the influence of the type and concentration of the CEs Joncryl and pyromellitic dianhydride (PMDA) on the viscosity and other rheological properties with a unique combination of different methods based on industrial samples originating from recycled PET bottles and trays. The resulting chain-extended thermoplastics were characterized by a combination of differential scanning calorimetry, viscometry, cone plate rheometry, pyrolysis-gas chromatography-mass spectroscopy, optical photo-thermal infrared spectroscopy, 13 C solid-state-and 1 H NMR liquid spectroscopy, and size exclusion chromatography. For a recycled PET mixture containing bottle and tray materials, our investigations have shown that a significantly better effect for chain elongation can be achieved with Joncryl compared to PMDA. This can presumably be attributed to water molecules formed during the use of PMDA, which accelerate the degradation of PET. The storage modulus values are therefore significantly higher for the samples with Joncryl compared to PMDA. The results of this study show that chain extension with Joncryl proceeds better compared to the reaction with PMDA.

Category

Academic article

Client

  • EU – Horizon Europe (EC/HEU) / 730292
  • Research Council of Norway (RCN) / 318730

Language

English

Author(s)

Affiliation

  • SINTEF Industry / Materials and Nanotechnology
  • SINTEF Industry / Process Technology
  • Gottfried Wilhelm Leibniz Universität Hannover

Date

05.07.2024

Year

2024

Published in

Industrial & Engineering Chemistry Research

ISSN

0888-5885

Publisher

American Chemical Society (ACS)

Volume

63

Issue

28

Page(s)

12277 - 12287

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