Recent Advances in Nature-Inspired Synthesis of Fully Bio-Based Moisture-Resistant Wood Adhesivesby Using Tannic Acid

In recent years, attention to the development of environmentally friendly materials, especially in the adhesive industry, has increased dramatically. The wood industry is one of the largest consumers of adhesives. Synthetic wood adhesives are primarily based on urea-formaldehyde and melamine-formaldehyde resins, which release formaldehyde during manufacturing and use that is highly harmful to human health. In recent years, regulations and guidelines prohibiting the use of formaldehyde-releasing compounds have been established in most countries. Consequently, extensive research has been conducted to replace formaldehyde-based wood adhesives. Tannic acid-based (TA) adhesives, as a natural and abundant compound, have gained attention as a promising material for the synthesis of fully bio-based wood adhesives due to their unique properties, such as high adhesion, moisture resistance, biocompatibility, and antimicrobial properties. In this paper summarizes the latest advances in using tannic acid in producing moisture-resistant wood adhesives, inspired by natural structures and mechanisms is summarized. First, the properties of tannic acid and its role in improving adhesion and water resistance and then various methods of modifying tannic acid and combining components to achieve high-performance adhesives are reviewed. Additionally, the effect of combining tannic acid with other natural materials, such as proteins, polysaccharides, and nanoparticles, to enhance the mechanical properties and moisture resistance is discussed. This study demonstrates that tannic acid-based adhesives have significant potential as a sustainable and efficient alternative to petroleum-based synthetic adhesives in the wood industry, particularly in humid or underwater environments.