Publication in J. Am. Chem. Soc.

An innovative and sustainable process for the production of polyurethane foams



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Produced for decades using toxic isocyanates, polyurethane (PU) foams remain essential in our daily lives as insulation materials for floors, walls, and roofs, as well as for comfort applications such as mattresses, sofa padding, car seats, and sports shoe soles. While PU recycling channels are slowly developing, end-of-life management remains problematic. Additionally, many customers in the foam sector increasingly seek non-isocyanate and ideally bio-sourced products. Alternatives for producing these foams without isocyanates, more environmentally friendly and utilizing locally available resources while facilitating recycling, have long been sought. Beyond these challenges, new manufacturing methods must adapt to current industrial foam molding infrastructures.

The team of Christophe Detrembleur (WEL Research Institute – ULiège) recently developed the first process for producing recyclable polyurethane foams without isocyanates (NIPU) using water as a foaming agent (CO2). The foams are produced quickly from room temperature formulations. This technology uses water and a catalyst added to a formulation composed of cyclic carbonates (derived from CO2), amines (potentially bio-based), and other additives (bio-based or not). A portion of the cyclic carbonates is transformed into gas (CO2) which inflates the matrix, while the rest contributes to its formation and hardening. The foaming is exothermic and therefore very rapid, mimicking the traditional process based on isocyanates. This technology enables almost all PU foam applications, both rigid and flexible, and high-content bio-based foams (70 to 90%) can be easily produced in under 2 minutes.

This innovative technology is simple, modular, robust, and very easy to implement. It represents a realistic alternative for producing the next generation of foamed materials that meet new legislative requirements, social needs, and sustainability imperatives, all while leveraging locally available raw materials.

Reference : M. Bourguignonet al. , Cascade exotherms for rapidly producing hybrid nonisocyanate polyurethane foams from room temperature formulations, J. Am. Chem. Soc. (2024) 146 : 988–1000

Source: Communication from ULiège

Illustration : With authorisation from Christophe Detrembleur

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