Efficient room-temperature synthesis of crosslinked polyhydroxyurethanes from 5-membered cyclic carbonates without solvent or catalyst

We report the first solvent- and catalyst-free synthesis of crosslinked polyhydroxyurethanes (PHUs) at room temperature from five-membered cyclic carbonates (5CC). A trifunctional carbonate (tri-5CC) combined with tetraethyleneglycol diamine (tDA) formed homogeneous, gelled networks within 24 h (carbonate conversion = 90%, gel time = 6 h). By blending tri-5CC with a tetrafunctional analogue (tetra-5CC), we achieved tunable gel times (1-6 h) and crosslink densities. All systems completed crosslinking under ambient conditions within one month and displayed robust thermal and mechanical properties. Ambient moisture enhanced network formation, confirming the practical relevance of these systems. This study repositions carbonate-amine chemistry as a promising route for the room-temperature synthesis of isocyanate-free thermosetting polyurethanes.