Synthesis of Lignin Nanoparticles and Hydrogels

Abstract

The increasing consumption of raw materials and the concern about the environmental risks related to it have induced the search for alternative sustainable materials. Among the new sources of materials, lignin is an excellent example of biomass-derived materials; since it is the second most abundant biopolymer in the world and a non-expensive material, it is gaining attention as a sustainable material with a bright future. In this context, lignin-based nanoparticles and hydrogels exhibit interesting properties such as antimicrobial activity and biocompatibility and can thus replace some synthetic materials. Thus, they can be considered as promising biomaterials for a wide variety of applications in biomedicine and agriculture, among others. Lignin is a crosslinked polymer with many functional hydrophilic and active groups, such as hydroxyls, carbonyls and methoxyls, which can be used as active groups in the synthesis of biodegradable hydrogels. This chapter describes the main synthetic methods for the preparation of lignin-based hydrogels and nanoparticles. Different synthetic pathways based on their chemical and/or physical interactions are summarized. In addition, a brief review of their most recent applications is also provided.