Recent Advances in the Preparation, Properties, and Applications of Lignin-Based Hydrogels and Adhesives

Abstract

Lignin, as a renewable and environmentally friendly resource, serves as the primary source of aromatic compounds in nature. Harnessing lignin for high-value applications is essential for addressing energy and environmental challenges, and thus it is crucial to develop high-performance lignin-based materials through advanced material technologies. Among various lignin-based materials, hydrogels and adhesives have garnered significant attention due to their simple preparation methods and excellent properties. This review summarizes recent advancements in the preparation strategies, structural features, functional attributes, and applications of lignin-based hydrogels and adhesives. First, the structural characteristics and utilization methods of lignin are analyzed based on its source. Then, the preparation methods of lignin-based hydrogels are detailed, offering an in-depth comparison of the advantages and disadvantages of physical and chemical crosslinking methods. The functional attributes of lignin-based hydrogels and their applications in fields such as flexible sensing and energy storage are thoroughly reviewed. Additionally, this review discusses the preparation methods of lignin-based adhesives and their ongoing development for wood bonding applications. Finally, future directions for the development of lignin-based hydrogels and adhesives are explored. This review provides fundamental knowledge on the preparation, application, and development of lignin-based hydrogels and adhesives, offering valuable insights for the efficient conversion and utilization of lignin.