Green and facile method for valorization of lignin to high-performance degradable thermosets

As the most abundant natural aromatic polymer on the Earth, lignin is expected to replace fossil resources for the preparation of high-performance thermosetting polymers. Numerous studies have been devoted to utilizing lignin through depolymerization and chemical modification; nevertheless, the green and facile valorization of lignin to high value products is still a challenge. Herein, we developed a straightforward approach to directly use lignin to prepare thermosetting polymers combining high performance and excellent degradability. In a green acetone-water-acetic acid component solvent system, lignin-based thermosets were facilely prepared via cross-linking reactions between lignin and glycidoxypropyltrimethoxysilane (KH560). The thermosets exhibited outstanding thermal and mechanical properties with a glass transition temperature of similar to 214 degrees C, a tensile strength of similar to 45 MPa and a Young's modulus of similar to 2274 MPa, and these properties can be easily manipulated by adjusting the ratio of lignin to KH560. The presence of Si-O-C bonds and ester bonds in the network structure imparts excellent degradability to the thermosets in alkaline aqueous solution. This work provides a green and facile strategy to directly integrate lignin into cross-linked networks, which discloses a new idea for the valorization of lignin to value-added materials.