Chemically Recyclable Biobased Non-Isocyanate Polyurethane Networks from CO₂ -Derived Six-membered Cyclic Carbonates

Area of Science:

• Polymer Chemistry
• Sustainable Materials Science
• Green Chemistry

Background:

• Non-isocyanate polyurethanes (NIPUs) offer a sustainable alternative to traditional polyurethanes by avoiding toxic isocyanates.
• The aminolysis of cyclic carbonates presents a viable route for NIPU synthesis.

Purpose of the Study:

• To synthesize and characterize novel NIPUs from renewable bis(6-membered cyclic carbonates) (iEbcc) and various amines.
• To evaluate the mechanical properties, thermal stability, remoldability, and degradability of the synthesized NIPUs.

Main Methods:

• Synthesis of NIPUs via aminolysis of renewable iEbcc with amines.
• Characterization of mechanical properties and thermal stability.
• Assessment of remolding via transcarbamoylation and chemical degradation via alcoholysis.

Main Results:

• NIPUs derived from iEbcc exhibit excellent mechanical properties and thermal stability.
• The NIPUs demonstrate efficient remolding capabilities, with one sample retaining 90% tensile stress after three cycles.
• Chemical degradation yields high-purity bi(1,3-diol) precursors (>99% purity, >90% yield), which can be used to regenerate NIPUs.

Conclusions:

• A novel, isocyanate-free synthetic strategy for NIPUs using renewable isoeugenol and CO2 is presented.
• The developed NIPUs are recyclable and degradable, supporting a circular economy approach.
• This work highlights a promising pathway for creating advanced NIPU networks with enhanced sustainability.