Development of green-solvent-processable vitrimer-like polyurethane elastomers with reversible covalent adaptable network for fiber applications

초록

Conventional fiber-grade polyurethanes (PUs) require covalent crosslinking for mechanical durability but rely on toxic, high-boiling dipolar aprotic solvents, complicating recycling and increasing energy and carbon costs. Herein, we report pseudo-vitrimer PU elastomers incorporating reversible disulfide metathesis to form covalent adaptable networks (CANs), enabling dissolution in green, low-boiling solvents such as diethyl carbonate (DEC) and tetrahydrofuran (THF). By optimizing asymmetric/symmetric hard segment ratios and disulfide content, we achieve solvent/heat-induced topological rearrangement without compromising elastic integrity. Systematic variation of disulfide ratio, hard-segment symmetry, and branching density revealed a solvability-mechanics trade-off; nonetheless, an optimized hybrid formulation achieved fiber-grade performance (37.3 MPa tensile strength, 621% elongation) and similar to 0.5 g d(-1) tenacity when wet spun, while being readily processable in heated THF/DEC at <= 70 degrees C. First-principles evaporation analysis predicted similar to 26-36% lower energy consumption for solvent removal compared to conventional solvents. In vitro immune assays indicated no significant cytotoxicity, while composting tests also demonstrated mass-loss behavior under composting conditions. This work demonstrates a viable PU architecture integrating mechanical robustness, green solvent processability, and recyclability. Furthermore, it highlights a sustainable/circular route for fiber-grade PU production.

키워드