Eco-friendly flame retardant additives for epoxy resin nanocomposites

Flame retardants (FRs) are a diverse group of chemicals used as additives in a wide range of products to inhibit, suppress, or delay ignition and to prevent the spread of fire. We have developed a flame-retardant epoxy resin whose flame retardancy is greatly enhanced by adding fly ash (a by-product from thermal power plants). Applying the fly ash eliminates the need to use current retardants such as organic halogen compounds and thus promotes the perceived environmental safety of flame retardant epoxy resin. Some commercial additives used today are hazardous to humans and the environment, and their extensive application is limited by their negative effects on polymer mechanical properties. Accordingly, identifying materials that are environmentally friendly and harmless to humans has become urgent need. Some alternative additives that are gaining research interest are clay and fly ash, which are natural and recyclable resources that can enhance the FR properties of other polymers. However, room for improvement is always present as the related technology is continually being developed. This review focuses on studies aiming to enhance the flame retardancy of epoxy resin using eco-friendly additives (Fly ash, Multi-Walled Carbon Nanotube, nanoclay). Fly ash have been demonstrated to act as an effective/synergistic co-additive in some FR applications and could thereby contribute to reducing the loading of FRs in products and improving their performance. Flame retardant additives of Fly ash were embedded in epoxy resin-Fly ash to improve the resin’s resistance to oxidation.