It is best to choose a flame retardant based on which flame retardant mechanism is suitable for the properties of the flame retardant.
1. Endothermic mechanism
Some flame retardants will decompose to form water when heated. The water evaporates and takes away a large amount of heat, thereby achieving the flame-retardant effect. This is the same principle as using water to extinguish fires. Common flame retardants of this type include borax, hydrated alumina, etc.;
2. Coverage effect
Some flame retardants will decompose when heated to form a stable covering layer, which insulates the material from oxygen, thereby achieving a flame retardant effect. Commonly used flame retardants include phosphate ester compounds and fire-retardant foam coatings;
3. Dilution effect
Some flame retardants will decompose when heated to generate a large amount of non-flammable gases (carbon dioxide, ammonia, chlorine chloride, etc.), diluting the air around the material and greatly reducing the concentration of oxygen, thereby achieving a flame retardant effect. This is similar to that of dry powder fire extinguishers. The principle is the same. Common flame retardants include amine phosphate, amine chloride, amine carbonate, etc.;
4 inhibitory effect
The combustion of some polymer materials is mainly a free radical chain reaction. Some substances can capture active intermediates of the combustion reaction, inhibit the free radical chain reaction, and reduce the burning speed until the flame is extinguished. Commonly used flame retardants include bromine, chlorine, and other organic halogen compounds.
