Flame Retardants for polymeric materials

A large number of RF flame retardants are available, enabling polymeric materials incorporating them to be used in applications that may represent a fire hazard. The incorporation of RFs is designed to satisfy standardized fire reaction tests. RFs are often adapted to the type of use of the object ultimately manufactured, and not linked to intrinsic thermodynamic values. Initial concerns on the part of manufacturers and legislators focused on the effectiveness of flame retardants in terms of intrinsic performance in terms of reaction to fire, smoke emission, intrinsic toxicity of RF and control of changes in polymer properties linked to their use. Since the 1990s, environmental and toxicological aspects have played an increasingly important role in the development, use and, more generally, the life cycle of flame-retardant polymer materials. These issues have led to the withdrawal of certain types of FR and encouraged the emergence of new solutions. Due to the considerable growth of flame-retardant plastics and composites in the waste stream, particularly in Waste Electrical and Electronic Equipment (WEEE), specific regulations have emerged to control their recycling. Similarly, the use of new flame-retardant systems including nanoparticles in waste plastics has recently led to research into adapting incinerators to new formulations of flame-retardant materials.

After presenting basic data on the reaction to fire of polymers and their main degradation pathways, general methods for improving their reaction to fire are discussed in this article. The various families of flame retardants are described, together with their mechanisms of action and possible synergies. Environmental and toxicological aspects are discussed at the end of the article.