Soft foam polyurethane recycling and foaming in reactive extrusion using partial aminolysis and a latent cross-linking chemistry
Abstract
Polyurethane (PU) foams are widely used as thermosets and yet poorly recycled due to their generally cross-linked nature and to the difficulty to recover their isolated monomers from chemical recycling processes. A mechanochemical recycling process was demonstrated in three steps in an internal mixer; partial aminolysis, cross-linking and foaming. Partial aminolysis was successfully demonstrated using a cycloaliphatic diamine and yielded a melt-processable PU with gel content (GC) of 54.4 % using as low as 6 wt% of diamine from a pristine PU with 94.1 % GC. The material was then efficiently cross-linked by blending it with a blocked isocyanate based on 4.4’-methylenebis (phenyl isocyanate) at 100 °C then triggering its reactivity at 160 °C to yield a material with GC of 84.7 %. The blocked isocyanate unblocking kinetics were assessed using rheometry, and revealed a partial reactivity even at 100 °C. The mechanical properties of the cross-linked recycled PU exhibited significantly improved properties as a consequence of network reformation. Finally, the concomitant use of a chemical blowing agent with blocked isocyanate allowed to yield a cross-linked recycled PU foam as a final step of mechanical processing. The strong reactivity of the blocked isocyanate appeared to limit marginally the foaming. Finally, the cross-linking and foaming process was performed successfully in one-step in a single screw extruder. This study demonstrates the potential of mechanical and chemical hybrid processes as short-loop recycling processes for thermosets.
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BibTeX
@article{pingret2026soft,
title = {{Soft foam polyurethane recycling and foaming in reactive extrusion using partial aminolysis and a latent cross-linking chemistry}},
author = {Morgane Pingret and Pascal Tiquet and Pierre Piluso},
journal = {ACS Sustainable Resource Management},
year = {2026},
month = aug,
doi = {10.1021/acssusresmgt.6c00057},
url = {https://cea.hal.science/cea-05759655v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Soft foam polyurethane recycling and foaming in reactive extrusion using partial aminolysis and a latent cross-linking chemistry
AU - Morgane Pingret
AU - Pascal Tiquet
AU - Pierre Piluso
PY - 2026
DA - 2026/08/04
JO - ACS Sustainable Resource Management
DO - 10.1021/acssusresmgt.6c00057
UR - https://cea.hal.science/cea-05759655v1
AB - Polyurethane (PU) foams are widely used as thermosets and yet poorly recycled due to their generally cross-linked nature and to the difficulty to recover their isolated monomers from chemical recycling processes. A mechanochemical recycling process was demonstrated in three steps in an internal mixer; partial aminolysis, cross-linking and foaming. Partial aminolysis was successfully demonstrated using a cycloaliphatic diamine and yielded a melt-processable PU with gel content (GC) of 54.4 % using as low as 6 wt% of diamine from a pristine PU with 94.1 % GC. The material was then efficiently cross-linked by blending it with a blocked isocyanate based on 4.4’-methylenebis (phenyl isocyanate) at 100 °C then triggering its reactivity at 160 °C to yield a material with GC of 84.7 %. The blocked isocyanate unblocking kinetics were assessed using rheometry, and revealed a partial reactivity even at 100 °C. The mechanical properties of the cross-linked recycled PU exhibited significantly improved properties as a consequence of network reformation. Finally, the concomitant use of a chemical blowing agent with blocked isocyanate allowed to yield a cross-linked recycled PU foam as a final step of mechanical processing. The strong reactivity of the blocked isocyanate appeared to limit marginally the foaming. Finally, the cross-linking and foaming process was performed successfully in one-step in a single screw extruder. This study demonstrates the potential of mechanical and chemical hybrid processes as short-loop recycling processes for thermosets.
SN - 2837-1445
ER -