Chemically Recyclable Polyurethane Foams from Sustainable Polymer

Polyurethanes (PUs), a versatile class of polymers, commonly
appear as rigid or flexible foams for widespread applications in
transportation, automotive, and consumer industries. The attributes that make
PU foams desirable, namely their low density and durability, pose inherent
issues in their end-of-life processing. In order to mitigate the widespread
practice of incinerating or landfilling these thermoset foams, we present the
synthesis of a sustainable PU foam that can be chemically recycled. Poly(𝛾-methyl-𝜺-caprolactone)-based foams can undergo a straightforward
depolymerization process to afford the starting monomer in high purity and
yield. We also demonstrate that these foams can be synthesized to exhibit a
range of mechanical properties. By adjusting the isocyanate index and
surfactants in the formulations, we create an array of foams with different compressive
strengths, cell morphologies, and densities. PU foams from poly(𝛾-methyl-𝜺-caprolactone) thus present a robust and sustainable alternative
to traditional petroleum-based PUs.