Robust and Recyclable Polymers with Mechanically Triggered Degradation

Abstract

The environmental persistence of synthetic polymers has reached crisis levels, with conventional degradation strategies struggling to reconcile material durability with end-of-life recyclability. This study proposes a molecular design strategy: dynamic hydrogen bonds impart mechanical strength and thermal stability, while post-polymerization modification unlocks ultrasound-triggered degradation of the mechanophore. By strategically integrating mechanophores via ring-opening metathesis polymerization (ROMP), we develop a mechanically triggered degradable polymer system exhibiting multifunctionality. This architecture demonstrates: (1) Incorporation of hydrogen-bonded crosslinkers significantly elevates the glass transition temperature (Tg) while dramatically enhancing mechanical robustness; (2) The amide bond in the lactam unit can be modified via post-polymerization to achieve a nearly quantitative functional group conversion, thereby effectively “unlocking” its ultrasonic degradability; (3) Degraded oligomers with specific functional end groups can be readily repolymerized to form high-molecular-weight polymers. This work establishes a framework for sustainable polymer design, where noncovalent design of the polymer enables simultaneous optimization of performance metrics and environmental compatibility.