Thiruvananthapuram, India – A group at the Vikram Sarabhai Space Centre’s polymers and special chemicals group has developed a scalable process for making self-blown non-iso polyurethane foams.
Resorcinol diglycidyl ether, a cyclic carbonate, was reacted with amine-terminated oligomeric phenyl hydroxyamine (AOPHA) to make the polymer. This reaction releases CO2, causing the foaming. The result is a flexible poly(hydroxyurethane) foam.
They found that the urethane linkages are formed by the reaction between a cyclic carbonate and the amine group of AOPHA. At temperatures above 100°C, AOPHA’s hydroxyl group also reacts, with another cyclic carbonate, to form beta-hydroxyether linkages and releasing CO2. This is what leads to the formation of the foam.
The flexible foam is thermally stable to at least 250°C. It has an open-cell structure, with a density of 480kg/m3. Its adhesive nature is as good, or better, than conventional PU foams, at 1.2–2.0MPa, they said.
The work has been published in the journal Material Letters: X.