One-pot synthesis of lignin-derived fully bio-based dynamic dual-network polymers via synergistic side reactions and star-shaped architectural design

Abstract

The valorization of lignin into high-performance polymeric materials remains a significant challenge, primarily due to the inherent complexity of conventional synthetic methodologies and the non-reprocessable nature of the derived polymers. In this study, we present a convenient one-pot strategy to access fully bio-based lignin-integrated polymers endowed with reprocessability. This approach leverages a side reaction, free radical termination, during the synthesis of star-shaped lignin graft copolymers via radical polymerization, enabling the initial formation of a primary permanent network and concurrently enhancing monomer utilization (95.6% conversion vs. 62.1% in conventional star polymers). Subsequently, carboxylic acid-terminated poly(lactic acid) oligomers are employed as green cross-linking agents to establish a secondary adaptive network via transesterification reactions. The resulting dual-network polymers exhibit tunability in mechanical properties and excellent reprocessability while retaining structural integrity. Notably, these dual-network systems demonstrate an 18.5 ± 1.9-fold enhancement in mechanical strength compared to their linear polymer counterparts. Moreover, these materials demonstrate remarkable super-hydrophobicity (contact angle >108°), enhanced thermal stability, and distinctive light-responsive behavior. This work presents a paradigm-shifting methodology that strategically repurposes side-reaction pathways to synthesize sustainable polymers, advancing the development of sustainable materials for circular economies.