Use of Diels-Alder Chemistry for Thermoreversible Cross-Linking of Rubbers: The Next Step toward Recycling of Rubber Products?

L. M. Polgar, M. van Duin, A. A. Broekhuis, F. Picchioni*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

167 Citations (Scopus)

Abstract

A proof of principle for the use of Diels-Alder chemistry as a thermoreversible cross-linking tool for rubber products is demonstrated. A commercial ethylene-propylene rubber grafted with maleic anhydride has been thermoreversibly cross-linked in two steps. The pending anhydride rings were first modified with furfurylamine to graft furan groups onto the rubber backbone. These pending furans were cross-linked with a bismaleimide via a Diels-Alder coupling reaction. The newly formed Diels-Alder cross-links break at elevated temperatures (>150 degrees C) and can be re-formed by thermal annealing (50-70 degrees C). Reversibility of the rubber network was proven with infrared spectroscopy and on the basis of the mechanical properties. Furthermore, reversibility was also shown in a practical way, i.e., by cutting the used material into pieces and pressing them into new samples displaying comparable mechanical properties (impossible for conventionally cross-linked rubbers). The physical properties of the resulting products are comparable to those of conventionally cross-linked EPDM rubber and superior compared to those of their non-cross-linked precursors.

Original languageEnglish
Pages (from-to)7096-7105
Number of pages10
JournalMacromolecules
Volume48
Issue number19
DOIs
Publication statusPublished - 13-Oct-2015

Keywords

  • REVERSIBLE CLICK CHEMISTRY
  • MALEATED ETHYLENE/PROPYLENE COPOLYMERS
  • BEARING FURAN MOIETIES
  • SOLID-STATE H-1-NMR
  • MALEIC-ANHYDRIDE
  • NATURAL-RUBBER
  • POLY(STYRENE-CO-MALEIC ANHYDRIDE)
  • CHAIN ENTANGLEMENTS
  • REACTIVE EXTRUSION
  • DEVULCANIZED EPDM

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