Bioinspired Dual-Stimulus-Responsive Macromolecular Engineering Enables Chemically Recyclable, High-Performance and Fire-Retardant Plastic

Sustainable circular economy, advanced fire safety, and integrated high performance of plastics are gaining increasing global attention. Inspired by the stimulus-responsive defense of natural organisms, we demonstrate an efficient biomimetic strategy to build life-cycle-managed polycarbonate plastics with integrated high performance and fire safety during the service stage and easy recyclability at the end of life. The key is that the designed dual-stimulus-responsive phosphonium-modified macromolecule (PBSP) can release flame retardants on demand under high temperature stimuli in fire or release catalysts on demand under chemical stimulus of ethylene glycol. With only 3 wt % PBSP added, polycarbonate plastics not only exhibit extremely high fire safety (32.1% limiting oxygen index) but also show excellent transparency (>85% transmittance), super heat resistance (145 °C glass transition temperature), and increased tensile strength (86.0 MPa) during the service stage. At the end of life, under the chemical stimulus of ethylene glycol, PBSP automatically releases the pendant phosphonium catalyst to trigger the depolymerization of polycarbonate, achieving ultrahigh atom-economic recycling. By stimulus-responsive biomimetic design, this work opens a new perspective for constructing advanced functional materials with integrated safety, high performance, and easy recyclability, paving the way for sustainable materials development and the global circular economy.