Upcycling Waste Thermosetting Polyimide Resins into High‐Performance and Sustainable Low‐Temperature‐Resistance Adhesives

Thermosetting polyimide (PI) has attracted extensive attention for its excellent properties, but the approaches to its end-of-life management are not sustainable, posing great threat to the ecosystem. Herein, this work proposes a mild, sustainable, and full recovery path for recycling waste carbon fiber reinforced phenylethynyl end-capped PI resin composites. In addition to recycling reaction reagent and woven carbon fiber, degraded products (DPETI) can be fully and directly used as high-performance and sustainable adhesives. DPETI exhibits strong adhesion to various surfaces, with a maximum adhesion strength of 1.84 MPa. Due to the strong supramolecular polymerization behavior without solvent dependence, DPETI demonstrates higher adhesive strength of 2.22 MPa in the extreme environment (-196 °C), which is maintained even after 10 cycles. This work sparks a new thinking for plastic wastes recycling that is to convert unrecyclable wastes into new and sustainable materials, which has the potential to establish new links within circular economies and influence the development of materials science.