Tannic acid-enriched polyurethanes: Synthesis, properties, and application potential

Polyurethanes find wide application in various industries, including transportation, automotive, medical, sports, and construction, due to their remarkable tailor-made properties, processability, and biocompatibility. Tannic acid, a natural and non-toxic polyphenolic compound, possesses many beneficial properties, including the promotion of tissue repair, flame resistance, corrosion inhibition, and desired biocompatibility and biodegradability. However, the utility of tannic acid is limited due to its limited environmental stability, inherent biodegradability, and sensitivity to external disturbances. To enhance its functional properties, tannic acid is frequently subjected to chemical modification or incorporated into polymeric matrices and composite systems. “Incorporating tannic acid into polyurethane matrices imparts a broad spectrum of desirable properties for different applications, such as antimicrobial and anti-inflammatory activity, improved biocompatibility, increased thermal stability, corrosion resistance, and flame retardancy.”A variety of products, including hydrogels, elastomers, fibers, and foams, along with composites derived from tannic acid and polyurethanes, have been developed for diverse applications. This review highlights the key properties of tannic acid and summarizes recent research on tannic acid–based polyurethanes, with emphasis on their synthesis strategies and applications in antibacterial coatings, wound dressings, tissue engineering, flame retarded polymers, water purification, and food packaging.