CO₂-Blown Nonisocyanate Polyurethane Foams

Polyurethane (PU) foams are produced from toxic, petrochemical- and phosgene-derived isocyanates. Although nonisocyanate polyurethane (NIPU) has shown promise as a replacement for traditional PU, the synthesis of NIPU foams has not been widely studied due to the difficulties in replicating the foaming process of PU, in situ CO₂ production through the hydrolysis of isocyanates. Hereby, we report the synthesis of amine-CO₂ adducts and their CO₂ adsorption-desorption characteristics under different conditions. The results show that the amine-CO₂ adducts can exhibit up to 87% CO₂ desorption at 60 °C after aminolysis with cyclic carbonate. The amine-CO₂ adduct is used as both a foaming agent and a comonomer to obtain low-density foams (0.203-0.239 g·cm^-3) after heating at 50-60 °C for 24-48 h. This marks the successful synthesis of in situ CO₂-blown NIPU foams using an amine-CO₂ adduct.