Unlocking the Potential of Lignin in Material Applications via its Simultaneous Isolation and Multi-Functionalization

During biomass fractionation lignin undergoes uncontrolled side reactions and loss of chemical functionalities that result in the isolation of a highly condensed aromatic polymer. Thus, it is generally necessary to perform additional functionalization reactions on the remaining active sites of isolatedlignin to enhance its reactivity towards other materials. Even when additional functionalization reactions are performed, high-performance lignin-based materials are still difficult to obtain. Here we show that by using a multifunctional aldehyde assisted fractionation process (AAF) we can isolate bi-functional lignins with controlled chemical structures and added functionalities, in one step from biomass. We used these lignins to produce new lignin-gelatin- based hydrogels with possible applications in soft-tissue engineering. These hydrogels have improved and controllable mechanical, temperature-resistant, adhesive and self-healing properties based on the functionalities imparted on the lignin during extraction. We hence demonstrate the importance and potential of controlling multiple functionalities on lignin during extraction, paving the way for new and high-performance applications of this polymer.