DNA: Future Bio-Macromolecule Flame Retardant

The search for novel efficient flame retardants, showing low environmental impact, and exploiting bio-derived sources, has pushed academia towards the exploration and exploitation of new performing systems. In the last decade, biomacromolecules and bio-derived products have been thoroughly investigated for their potential fireproof properties. In this quest therefore, deoxyribonucleic acid (DNA) has clearly demonstrated its suitability for protecting different polymer substrates from exposure to a direct flame or an irradiative heat source. Undoubtedly, the structure of DNA and nuclei acids mimics that of an intumescent system, as it consists of nitrogen-containing bases (i.e., adenine, cytosine, guanine, and thymine), which can release ammonia, (poly)saccharide deoxyribose units that behave as carbon sources and blowing systems (upon heating they undergo dehydration, promoting the release of water and favoring charring), and phosphate groups that can give rise to phosphoric acid, acting as char former. This chapter reviews the current state of the art about the use of DNA as an effective flame retardant for different types of polymers (namely, bulk thermoplastics and thermosets, textiles, and foams). Finally, some of the present limitations of the use of these biomacromolecules will be discussed, as well as some viewpoints for the forthcoming years.