Chain Flexibility as a Fundamental Descriptor for Mild Depolymerization of Polyesters and Polycarbonates

High Resolution Image Download MS PowerPoint Slide The chemical inertness of polyesters and polycarbonates hinders their sustainable recycling under mild conditions. While solvent-assisted depolymerization shows promise, its mechanism remains poorly understood, particularly regarding the macromolecular structure. This study identifies chain flexibility as a critical factor in enabling mild depolymerization, as it facilitates solvent-mediated disentanglement and conformational mobilization. We demonstrate this principle through model systems: amorphous bisphenol-A polycarbonate (BPA-PC) and semicrystalline poly(ethylene terephthalate) (PET). Structural analyses correlate this enhancement with reduced chain rigidity and increased solvent accessibility. A dissolution−reprecipitation strategy was developed to lock polymers into high-flexibility conformations, enabling efficient catalyst-free hydrolysis under ambient conditions. The universality of this chain flexibility-driven mechanism was further validated using polylactic acid (PLA) and various postconsumer waste products. These findings establish chain flexibility as a fundamental descriptor for depolymerization, offering mechanistic insight and a practical pathway toward closed-loop plastic recycling.