Abstract

Conventional synthetic adhesives are indispensable to modern manufacturing, yet many depend on nonrenewable feedstocks and some contain constituents of health or environmental concern. Lignin is an abundant renewable aromatic polymer with phenolic and aliphatic hydroxyl groups, an aromatic framework, and potential antioxidant activity. These features support covalent curing, intermolecular association, and interfacial interactions in adhesive formulations. This review examines how biomass origin, isolation history, fractionation, and chemical modification influence lignin structure, reactivity, solubility, compatibility, curing behavior, and interfacial and bulk performance. It separates adhesion at the substrate interface from cohesion within the cured network and evaluates trade-offs among bonding performance, processability, feedstock variability, reagent and solvent demand, and environmental benefit. The analysis identifies the material specifications, test controls, and processing requirements needed for reproducible, scalable, and commercially credible lignin-based adhesives.

Keywords: technical lignin, isolation history, structure–property relationships, curing chemistry, sustainable adhesives