[en] Finding new chemistry platforms for easily recyclable polymers has become a key challenge to face environmental concerns and the growing plastics demand. Here, we report a dynamic chemistry between CO2-sourced alkylidene oxazolidones and thiols, delivering circular non-isocyanate polyurethane networks embedding N,S-acetal bonds. The production of oxazolidone monomers from CO2 is facile and scalable starting from cheap reagents. Their copolymerization with a polythiol occurs under mild conditions in the presence of a catalytic amount of acid to furnish polymer networks. The polymer structure is easily tuned by virtue of monomer design, translating into a wide panel of mechanical properties similar to commodity plastics, ranging from PDMS-like elastomers [with Young's modulus (E) of 2.9 MPa and elongation at break (εbreak) of 159%] to polystyrene-like rigid plastics (with E = 2400 MPa, εbreak = 3%). The highly dissociative nature of the N,S-acetal bonds is demonstrated and exploited to offer three different recycling scenarios to the thermosets: (1) mechanical recycling by compression molding, extrusion, or injection molding─with multiple recycling (at least 10 times) without any material property deterioration, (2) chemical recycling through depolymerization, followed by repolymerization, also applicable to composites, and (3) upcycling of two different oxazolidone-based thermosets into a single one with distinct properties. This work highlights a new facile and scalable chemical platform for designing highly dynamic polymer networks containing elusive oxazolidone motifs. The versatility of this chemistry shows great potential for the preparation of materials (including composites) of tuneable structures and properties, with multiple end-of-life scenarios.
Disciplines :
Materials science & engineering
Author, co-author :
Habets, Thomas; Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, University of Liege, Sart-Tilman B6a, 4000 Liege, Belgium
Seychal, Guillem ; Université de Mons - UMONS > Faculté des Science > Service des Matériaux Polymères et Composites ; POLYMAT, University of the Basque Country UPV/EHU, Joxe Mari Korta Center, Avda. Tolosa 7, 20018 Donostia-San Sebastian, Spain
Caliari, Marco ; Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, University of Liege, Sart-Tilman B6a, 4000 Liege, Belgium ; POLYMAT, University of the Basque Country UPV/EHU, Joxe Mari Korta Center, Avda. Tolosa 7, 20018 Donostia-San Sebastian, Spain
RAQUEZ, Jean-Marie ; Université de Mons - UMONS > Faculté des Science > Service des Matériaux Polymères et Composites
Sardon, Haritz ; POLYMAT, University of the Basque Country UPV/EHU, Joxe Mari Korta Center, Avda. Tolosa 7, 20018 Donostia-San Sebastian, Spain
Grignard, Bruno ; Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, University of Liege, Sart-Tilman B6a, 4000 Liege, Belgium ; FRITCO2T Platform, University of Liege, Sart-Tilman B6a, 4000 Liege, Belgium
Detrembleur, Christophe ; Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, University of Liege, Sart-Tilman B6a, 4000 Liege, Belgium
R400 - Institut de Recherche en Science et Ingénierie des Matériaux
Funders :
HORIZON EUROPE Marie Sklodowska-Curie Actions Fonds De La Recherche Scientifique - FNRS Waalse Gewest
Funding text :
The authors of Liege thank FNRS for the financial support in the frame of the COSwitch project under grant T.0075.20. C.D. is a F.R.S.-FNRS Research Director, and J.-M.R. is a F.R.S.-FNRS Senior Research Associate. Computational resources have been provided by the Consortium des Équipements de Calcul Intensif (CÉCI), funded by the Fonds de la Recherche Scientifique de Belgique (F.R.S.-FNRS) under grant no. 2.5020.11 and by the Walloon Region. The authors would like to thank the financial support provided by the NIPU-EJD project; part of this project (composite preparation and recycling) has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. 955700. 2
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