Diamide-Containing Vinylogous Urethane Vitrimers with Excellent Mechanical Properties and Closed-Loop Recyclability

Vinylogous urethane (VU) vitrimer, as an emerging reprocessable material, exhibits excellent designability, reprocessability, recyclability, and wide potential applications. A critical challenge persisting in VU materials is harmonizing exceptional mechanical strength with robust recyclability and reprocessability. Here, a simple strategy was presented to synthesize VU vitrimers with excellent mechanical properties and good reprocessability through the incorporation of symmetrical diamide motifs into VU backbones. Dynamic mechanical analysis and tensile testing revealed outstanding mechanical properties, including a tensile strength of 112.2 MPa and a storage modulus of 2.5 GPa. The designed VU networks demonstrated full closed-loop recyclability via thermal reprocessing or acidic hydrolysis, retaining 80–90% of their initial mechanical integrity after two reprocessing cycles. This study provides a versatile molecular design paradigm for engineering high-performance reprocessable materials and extends its applicability to VU-based systems and other recyclable polymer platforms.