Tannin based polyphenolic bio-macromolecules: Creating a new era towards sustainable flame retardancy of polymers

Sustainable flame retardancy of polymeric materials is one of the thirsty, promising and challenging areas in today's fire safety world. Different researchers are trying to achieve that scientific beauty employing different research perspectives. Bio-based (bio-macromolecule) flame retardancy is one of the emerging and promising fields and continuously adding feathers in the crown of sustainable flame retardancy from the past decade. Bio-based flame retardants are sustainable. Tannin is an aromatic polyphenolic compound, one of the important and major active ingredients of most of the plant-based bio-macromolecules. As per reported documents, past few years have witnessed great flame retardancy potential of tannin and tannin based plant bio-macromolecules on textile, steel and other natural and synthetic polymeric materials. However, till date, no critical review has been registered on the compilation of the flame retardant performance of tannin and tannin based plant bio-macromolecule treated natural and synthetic textiles, polymeric substrates etc, This review report critically elucidates the thermal properties of tannic acid and in detail flame retardant performances of tannic acid (hydrolyzed and condensed), chemically modified tannic acid-treated textile, polymeric substrates. Besides, the review context also registers the mechanism involved behind the tannin based flame retardancy of different natural and synthetic polymeric substrates like cotton, wool, silk, epoxy resin, steel, polyester, nylon etc. Besides, some futuristic scientific suggestions and challenges also have been systematically discussed at the end part of this review manuscript.