Efficient and Robust Dynamic Crosslinking for Compatibilizing Immiscible Mixed Plastics through In Situ Generated Singlet Nitrenes

Creating a sustainable economy for plastics demands the exploration of new strategies for efficient management of mixed plastic waste. The inherent incompatibility of different plastics poses a major challenge in plastic mechanical recycling, resulting in phase‐separated materials with inferior mechanical properties. Here, this study presents a robust and efficient dynamic crosslinking chemistry that effectively compatibilizes mixed plastics. Composed of aromatic sulfonyl azides, the dynamic crosslinker shows high thermal stability and generates singlet nitrene species in situ during solvent‐free melt‐extrusion, effectively promoting C─H insertion across diverse plastics. This new method demonstrates successful compatibilization of binary polymer blends and model mixed plastics, enhancing mechanical performance and improving phase morphology. It holds promise for managing mixed plastic waste, supporting a more sustainable lifecycle for plastics. Bis‐aromatic sulfonyl azide crosslinkers decompose at typical polymer melt‐processing temperatures, forming reactive singlet nitrene intermediates for dynamic covalent crosslinking via direct C─H insertion. This solvent‐free, melt‐extrusion process efficiently installs dynamic siloxane crosslinks in polymer blends, reducing phase separation and enhancing mechanical performance, providing a robust and practical method for compatibilizing mixed plastics.