Cascade exotherms for rapidly producing hybrid non-isocyanate polyurethane foams from room temperature formulations

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 non-isocyanate polyurethane (NIPU) formulations composed of a CO2-based tri-cyclic carbonate, diamine, water and a catalyst, successfully addressed the isocyanate issue, however failed to provide foams at RT. Herein, we elaborate a practical solution to empower the NIPU foam formation in record timeframes from RT formulations. We generate cascade exotherms by the addition of a highly reactive triamine and an epoxide to the formulation of the water-induced self-foaming process. These exotherms, combined to a fast crosslinking imparted by the triamine and epoxide, rapidly raise the temperature to the foaming threshold and deliver hybrid NIPU foams in 5 minutes with KOH as catalyst. Careful selection of the monomers enables producing foams with a wide range of properties, as well as with an unprecedented high bio-based content up to 90 wt%. Moreover, foams can be upcycled into polymer films by hot-pressing, offering them a facile reuse scenario. This robust cheap process opens huge perspectives for greener foams of high bio-based contents, expectedly responding to the sustainability demands of the foam sector. It is potentially compatible to the retrofitting of industrial foaming infrastructures, which is of paramount importance to accommodate existing foam production plants and address the huge foam market demands.