High performance polyurethanes derived from aromatic acetal-containing polyols enabling closed-loop recycling†

Abstract

Polyurethanes (PUs) are widely employed across diverse industries due to their versatility, durability, and mechanical strength. Enhancing their thermal and mechanical performance holds great potential for expanding their applicability and unlocking new market opportunities. This study addresses two key challenges: limited availability of aromatic polyols for high-performance PUs and their recycling issues. Incorporation of aromatic content in polyether polyols has traditionally been difficult using conventional methods. Herein, we developed three novel aromatic acetal-containing polyols through a green and solvent-free protocol via the polycondensation of aldehydes and diols, using acidic heterogeneous catalysts. Resulting polyols, with tailored aromatic content, significantly improved the mechanical strength of PUs, while maintaining low viscosity and easy processability. Besides that, PUs synthesized from these polyols exhibited excellent thermal stability and remarkable water resistance under neutral conditions. Additionally, these materials demonstrated efficient closed-loop recyclability through a novel transacetalization-based depolymerization under mild acidic conditions, yielding high purity monomers in good yields. This work introduces innovative aromatic polyacetal polyols, offering a sustainable approach to high-performance PUs. The approach also leverages the wide availability of diols and aldehydes, enabling the design of PUs with superior properties and closed-loop recycling.