Sustainable and Scalable Synthesis of Acetal-Containing Polyols as a Platform for Circular Polyurethanes

Area of Science:

• Polymer Chemistry
• Materials Science
• Sustainable Chemistry

Background:

• Polyurethanes (PUs) are widely used but difficult to recycle chemically.
• Current recycling methods require harsh conditions and produce complex mixtures.
• Lack of efficient recycling hinders PU sustainability and circular economy goals.

Purpose of the Study:

• To develop closed-loop recyclable polyurethanes by incorporating cleavable acetal groups.
• To establish a sustainable and scalable synthesis for acetal-containing polyols (APs).
• To demonstrate the feasibility of closed-loop recycling for PU materials.

Main Methods:

• Synthesized acetal-containing polyols (APs) via aldehyde-diol polycondensation using heterogeneous catalysts.
• Prepared PU materials using APs and 4,4'-methylene diisocyanate (MDI).
• Investigated PU recyclability under acidic conditions and monomer recovery rates.

Main Results:

• Developed PUs with mechanical properties comparable to conventional PUs.
• Achieved excellent recyclability of PUs under acidic conditions.
• Recycled PUs yielded high monomer recovery rates (89% for 1,6-hexanediol, 84% for MDI precursor).
• Successfully demonstrated closed-loop recycling by synthesizing APs from recovered monomers.

Conclusions:

• Acetal-containing PUs offer a viable solution for closed-loop recycling.
• The developed synthesis method is sustainable and scalable.
• This approach significantly contributes to advancing a circular economy for polyurethanes.