Illinois, US – Scientists at Northwestern University have developed a way to make reprocessable self-blowing non-isocyanate polyurethane foams. They suggest that these polyhydroxyurethanes have potential as more benign alternatives to isocyanate-based PU foams.
The team said that by decoupling the aminolysis and thiol-decarboxylation of cyclic carbonates, reaction times could be cut from 20 hours to just 30 minutes. They managed to achieve the synthesis of the foam without impacting its morphological and physical properties.
By varying the concentration of thiol in the reaction mixture, they showed they could tune the morphological properties of the foam, including cell density and diameter, the open-cell ration, and the mechanical properties of both semi-rigid and flexible foams.
They also found that they could melt-reprocess the dynamic covalent foams into bulk films, with the full recovery of crosslink density.
The work has been published in the journal Polymer.
