Efficient room-temperature synthesis of crosslinked polyhydroxyurethanes from 5-membered cyclic carbonates without...

Area of Science:

• Polymer Chemistry
• Materials Science
• Green Chemistry

Background:

• Traditional polyurethane synthesis often relies on hazardous isocyanates and harsh conditions.
• Developing sustainable and safe alternatives for polymer production is a critical research area.

Purpose of the Study:

• To establish the first solvent- and catalyst-free synthesis of crosslinked polyhydroxyurethanes (PHUs) at room temperature.
• To explore the use of five-membered cyclic carbonates (5CC) and diamines for creating isocyanate-free thermosets.

Main Methods:

• Utilized a trifunctional cyclic carbonate (tri-5CC) and tetraethyleneglycol diamine (tDA) for network formation.
• Investigated blending tri-5CC with a tetrafunctional analogue (tetra-5CC) to tune properties.
• Monitored carbonate conversion and gel times under ambient conditions.

Main Results:

• Achieved high carbonate conversion (90%) and network formation within 24 hours.
• Demonstrated tunable gel times (1-6 hours) and crosslink densities by adjusting monomer ratios.
• Observed robust thermal and mechanical properties in the synthesized PHUs.
• Confirmed that ambient moisture positively influences network formation.

Conclusions:

• Successfully synthesized crosslinked PHUs under ambient conditions using a solvent- and catalyst-free approach.
• Repositioned carbonate-amine chemistry as a viable and sustainable route for isocyanate-free polyurethane production.
• Highlighted the practical relevance and potential of this method for developing advanced thermosetting materials.