Alginate as Flame Retardant: Synthesis, Structure, Properties, and Applications

Alginate serves as a structural component of brown algae and assist with the shape of the plant. Alginate is a hydrophilic anionic polysaccharide derived from brown algae, bacteria and has been attracting attention as a promising flame-retardant material in recent years. Alginate is an unbranched polysaccharide composed of two linear copolymer blocks, l-guluronic acid (G) and d-mannuronic acid (M), which provides better thermal stability and flame retardancy to polymer matrices. These properties enhance alginate's high temperature resistance, making it a strong choice for use in flame retardant applications. Alginate is a biodegradable material that acts as a flame retardant by releasing water vapor when exposed to heat or flame, helping the material cool and preventing the spread of fire. Alginate flame retardants typically produce very little smoke when exposed to fire, thus contributing to improved fire safety. The versatility of alginate is also demonstrated by its compatibility with a wide variety of materials, allowing easy integration into fibres, coatings, composites, and foams. Incorporation of alginates into these matrices significantly improves the fire performance of the resulting materials, making them an attractive solution for improving fire safety across a wide range of applications. As research continues to advance, the incorporation of alginate into matrix materials is expected to increase and advance fire safety progress and promote sustainable practices in all industries. This chapter discusses the flame retardancy of alginate incorporated in various polymer matrices, and the structure of alginate that makes it an excellent flame-retardant filler.