Hierarchical Dynamic Network Reconfiguration for Co-Rrecycling of Mixed Biodegradable Polyesters

Recycling biodegradable polyesters holds great potential for integration into future circular material systems, offering sustainable end-of-life solutions with biodegradability as a backup pathway. However, co-recycling mixed biodegradable polyesters remains challenging due to severe molecular-weight reduction and intrinsic incompatibility, which lead to substantial performance deterioration. Here, we present a hierarchical dynamic network reconfiguration strategy that reconstructs both intra- and interphase structures in mixed biodegradable polyesters. This approach integrates Zn2+-catalyzed co-alcoholysis with glycerol and subsequent dynamic cross-linking using lignin and isophorone diisocyanate. The lignin-derived nodes generate hierarchical network topologies that not only reconnect the cleaved polymer chains but also form interface networks that refine the phase morphology and enhance interphase stress transfer. For co-recycled poly(butylene adipate-co-terephthalate)/polylactide (70/30, wt/wt), the average dispersed domain size decreases from 3.3 μm in virgin blends to 108 nm, while the dispersed domain/interfacial thickness ratio is reduced from 10.0 to 1.2. The tensile strength and toughness are simultaneously enhanced by factors of up to 2.3 and 16.3, respectively, compared with those of virgin blends. The co-recycled materials also exhibit excellent thermal stability, long-term durability, reprocessability, and light-triggered self-healing capability. Furthermore, the strategy is applicable to diverse polyester mixtures and postconsumer products, providing a scalable and industrially viable route for sustainable co-upcycling and circular management of biodegradable plastics.