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. These reactions are first validated on model compounds and rationalized by DFT calculations. Various foams are then prepared and characterized in terms of morphology and mechanical properties, and the scope of the process is illustrated by modulating the composition of the reactive formulation. With impressive diversity and accessibility of the main components of the formulations, this new robust and solvent‐free process could open avenues for construction of more sustainable PU foams, and offers the first realistic alternative to the traditional isocyanate route.

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 in situ a thiol that generates the blowing agent (CO 2 ) 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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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. These reactions are first validated on model compounds and rationalized by DFT calculations. Various foams are then prepared and characterized in terms of morphology and mechanical properties, and the scope of the process is illustrated by modulating the composition of the reactive formulation. With impressive diversity and accessibility of the main components of the formulations, this new robust and solvent‐free process could open avenues for construction of more sustainable PU foams, and offers the first realistic alternative to the traditional isocyanate route.