Flame retardants either prevent or stop the burning process. This can be accomplished with two different mechanisms:
In this mechanism the flame reatardant material spends the heat occurring at the burning potential area. Flame retardants use the heat occurring in te enviroment and therefore decreases the heat of enviroment. In this category aluminium trihydroxide and magnesium hydroxide are the choices. These materials reveal water vapour at temperatures of 200°C to 300 °C, the reaction that produces water vapour is endothermic therefore uses the heat energy that occurs in the burning enviroment.
2Al(OH)3 → Al2O3 + 3H2O
The revealed water vapour decreases the concentration of the fuel in the burning zone and hinders the propagation of the flame.
This type of flame retardants change the chemistry of the burning process. The flame retardants expose Cl and Br type radicals in gas form and these gaseous products react with H and OH and renders them inaffective for burning. Also the additives such as clay results to ash formation which hinders the propagation of the flame.