Mechanically Robust and Chemically Recyclable Polyhydroxyurethanes from CO₂-Derived Six-Membered Cyclic Carbonates.

Area of Science:

• Polymer Chemistry
• Sustainable Materials Science
• Green Chemistry

Background:

• Growing demand for sustainable materials and regulations favor isocyanate-free polyurethane alternatives.
• Aminolysis of cyclic carbonates offers a promising pathway to polyhydroxyurethanes (PHUs).

Purpose of the Study:

• To develop a novel shape memory polyhydroxyurethane (PHU) vitrimer with enhanced mechanical properties and chemical recyclability.
• To demonstrate a green, carbon-neutral synthetic strategy for PHUs using CO2.

Main Methods:

• Synthesis of bis(six-membered cyclic carbonate) of 4,4'-biphenol (BCC-BP) from bi(1,3-diol) precursors and CO2.
• Aminolysis of BCC-BP to form PHU vitrimers.
• Characterization of thermal, mechanical, and dynamic properties.
• Evaluation of shape memory behavior and chemical recyclability via alcoholysis.

Main Results:

• Achieved maximum breaking strength of 65 MPa and elongation at break of 452%.
• Demonstrated significant shape recovery, lifting a load 4700 times its own weight.
• Successfully regenerated bi(1,3-diol) precursors through alcoholysis, confirming chemical recyclability.

Conclusions:

• The developed PHU vitrimers possess outstanding combined mechanical performance and shape memory effects.
• The isocyanate-free, CO2-based synthetic route is environmentally friendly and supports carbon neutrality.
• This work validates a green approach for designing high-performance, recyclable PHU materials.