Recyclable, Fire-Resistant, Superstrong, and Reversible Ionic Polyurea-Based Adhesives

Carbon dioxide (CO2) as a sustainable comonomer for the synthesis of polycarbonates, polyurea, and polyurethane is attracting continuous interest, whereas the development of multifunctional polymers directly from CO2 remains challenging for its inherent inertness. Herein, we report the synthesis and characterization of a recyclable, nonflammable, superstrong, and reversible adhesive via the polycondensation of CO2 and an amino-functionalized ionic liquid. The resulting CO2-sourced ionic polyurea (CIPUa) with commutative urea groups and ionic species in the skeleton shows much higher shear strength on various substrates even below −80 °C than commercial hot-melt adhesives and excellent nonflammability and antibacterial ability than isocyanate-derived nonionic polyurea. CIPUa also demonstrates facile degradation in ZnSO4 aqueous solution and can be recycled into fresh CIPUa. These properties are mainly endowed by the enhanced electrostatic interaction and attenuated hydrogen bonds between the CIPUa chains. This study provides an effective strategy for designing a sustainable CO2-sourced ionic polymer with multiple functions for broad applications.