Biobased, High-Performance Covalent Adaptable Networks from Levulinic Acid and Amino Acids

Covalent adaptable networks (CANs) endow thermosets with recyclability (reprocessability and degradability) and are expected to address the issues of environmental pollution and resource waste triggered by the extensive use of thermosets. However, the contradiction between high performance and rapid reprocessing has always existed and is difficult to be resolved. Here we used biomass-derived levulinic acid and amino acids as feedstocks to synthesize fully biobased or high biobased content dual dynamic networks constructed by in situ generated Schiff base and ester bond. High cross-link density and hydrogen bonding enabled CANs with a high glass transition temperature and mechanical properties even without rigid loops in the network. In addition, the dual dynamic exchange reactions of the autocatalyzed transesterification by in situ generated tertiary amines and the Schiff base exchange contributed rapid reprocessing without external catalysts to the CANs. Moreover, the Schiff base also endowed the CANs with controllable degradation properties under acidic conditions.