Sustainable, Degradable, and Flame-Retardant Polyurethane Elastomer Enabled by Sustainable Chain Extender and Reactive Fire-Retardant

Abstract The development of polyurethane elastomers with excellent comprehensive properties, such as robust mechanical strength, high rebound resilience, fire retardancy, and aqueous degradability, is of great practical significance. Herein, we report the design and synthesis of a polyurethane elastomer exhibiting outstanding mechanical, thermal, and chemical properties, including high mechanical performance, intrinsic flame retardancy, strong adhesion capability, and aqueous and acid degradability. Specifically, a xylose-derived degradable chain extender (DHGX) and a P/N-containing reactive flame retardant (BHP) are rationally engineered into the polyurethane backbone to prepare the target elastomer (PU-DHGX-BHP). The as-prepared PU-DHGX-BHP exhibits a high tensile strength of 11.5 MPa, together with a high elongation at break of 1018% and a high toughness of 46.9 MJ m–3. Moreover, PU-DHGX-BHP achieves a V-0 flammability rating and demonstrates self-extinguishing behavior within 0.5 s. Owing to the dynamic hydrogen-bonding and π–π stacking interactions, PU-DHGX-BHP exhibits strong adhesion toward polar substrates, with a high peel strength of 41.1 N cm–1 on poly(vinyl chloride) (PVC) substrate. Furthermore, the incorporation of DHGX structures and urethane bonds into the polymer backbone enables PU-DHGX-BHP to undergo complete degradation in acidic solutions and partial degradation in aqueous environments, with xylose and glyoxylic acid recovered as degradation products. This study provides a feasible strategy for the development of degradable polyurethane elastomers derived from non-edible biomass sugars, opening avenues for the design of next-generation sustainable elastomers.