We report an approach to fabricate self-blown nonisocyanate polyurethane (NIPU) foams by capitalizing on the divergent chemistries of amines with cyclic carbonates─creating the polymer network─and thiolactone─delivering a thiol that generates the blowing agent (CO) by reaction with a cyclic carbonate. Multiple linkages (hydroxyurethanes, thioethers, and amides) are created within the polymer network by this domino process. This one-pot methodology furnishes flexible to rigid foams with open-cell morphology at moderate temperature. The foams are easily repurposed into films or structural composites by thermal treatment, showing the first example of recyclable NIPU foams. Remarkably, both the formation and the recycling of the thermoset foams do not necessarily require the use of a catalyst. This facile and robust process is opening new avenues for designing more sustainable PU foams and offers new end-of-life options by facile material repurposing.
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http://dx.doi.org/10.1021/acsmacrolett.1c00793 | DOI Listing |
J Am Chem Soc
January 2024
Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, University of Liege, Sart-Tilman B6a, Liege 4000, Belgium.
For decades, self-blown polyurethane foams─found in an impressive range of materials─are produced by the toxic isocyanate chemistry and are difficult to recycle. Producing them in existing production plants by a rapid isocyanate-free self-blowing process from room temperature (RT) formulations is a long-lasting challenge. The recent water-induced self-blowing of nonisocyanate polyurethane (NIPU) formulations composed of a CO-based tricyclic carbonate, diamine, water, and a catalyst successfully addressed the isocyanate issue, however failed to provide foams at RT.
View Article and Find Full Text PDFPolymers (Basel)
January 2023
IMED-Lab, Faculty of Sciences and Techniques, Cadi Ayyad University, Avenue Abdelkrim Elkhattabi, B.P 549, Marrakech 40000, Morocco.
Polyurethane foams (PUFs) are a significant group of polymeric foam materials. Thanks to their outstanding mechanical, chemical, and physical properties, they are implemented successfully in a wide range of applications. Conventionally, PUFs are obtained in polyaddition reactions between polyols, diisoycyanate, and water to get a CO foaming agent.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2022
Center for Education and Research on Macromolecules(CERM), CESAM Research Unit, University of Liège, Department of Chemistry, Sart-Tilman, B6A, 4000, Liège, Belgium.
For 80 years, polyisocyanates and polyols were central building blocks for the industrial fabrication of polyurethane (PU) foams. By their partial hydrolysis, isocyanates release CO that expands the PU network. Substituting this toxic isocyanate-based chemistry by a more sustainable variant-that in situ forms CO by hydrolysis of a comonomer-is urgently needed for producing greener cellular materials.
View Article and Find Full Text PDFACS Macro Lett
February 2022
Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, Department of Chemistry, University of Liège, Sart-Tilman, B6A, 4000 Liège, Belgium.
We report an approach to fabricate self-blown nonisocyanate polyurethane (NIPU) foams by capitalizing on the divergent chemistries of amines with cyclic carbonates─creating the polymer network─and thiolactone─delivering a thiol that generates the blowing agent (CO) by reaction with a cyclic carbonate. Multiple linkages (hydroxyurethanes, thioethers, and amides) are created within the polymer network by this domino process. This one-pot methodology furnishes flexible to rigid foams with open-cell morphology at moderate temperature.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2020
Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, University of Liège, Department of Chemistry, Sart-Tilman, B6A, 4000, Liège, Belgium.
Polyurethane (PU) foams are indisputably daily essential materials found in many applications, notably for comfort (for example, matrasses) or energy saving (for example, thermal insulation). Today, greener routes for their production are intensively searched for to avoid the use of toxic isocyanates. An easily scalable process for the simple construction of self-blown isocyanate-free PU foams by exploiting the organocatalyzed chemo- and regioselective additions of amines and thiols to easily accessible cyclic carbonates is described.
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