Why Aluminum Hydroxide Can Be Used As Flame Retardant

Aluminum hydroxide is an inorganic flame retardant additive with a large amount and a wide range of applications. It can not only achieve the effect of flame retardant in use, but also prevent smoke and drips. At the same time, it can also be widely used as a flame retardant in many fields, but many users do not understand its specific principle, so it will be introduced in detail next.

As a flame retardant, it can decompose chemically bound water (about 34.6%) at high temperature. This decomposition reaction is an endothermic reaction, so it can delay the thermal degradation rate of the polymer and slow down or inhibit the polymer. Combustion, inhibit the temperature rise of polymers, and promote carbonization and smoke suppression. In addition, the large amount of water vapor released can dilute the concentration of combustibles and reduce the contribution of combustible gases to combustion, resulting in reduced heat release and smoke generation in the system, which also helps to interrupt combustion.

When heated and decomposed, it releases water and absorbs a large amount of latent heat, which reduces the actual temperature of the flame on the surface of the material and slows down the rate of polymer degradation into low molecules, reducing the occurrence of combustibles; the uniformly released water vapor dilutes the surface oxygen. The concentration of the surface combustion can not be carried out, the initial decomposition temperature is about 205 ° C, and 320 ° C has basically completed the dehydration reaction, releasing crystal water, absorbing latent heat, reducing the temperature (that is, the "cooling technology in the flame retardant technology, resulting in The large amount of water vapor can dilute the combustible gas.

In short, under the action of the flame, the decomposition of the polymer filled into the polymer absorbs part of the heat released during the combustion process, which is equivalent to removing the heat from the polymer, thereby reducing the temperature of the polymer and slowing down the degradation rate. This dispersive endothermic chemical cooling effect is the main reason for its flame retardancy. The water vapor released by hydrogen decomposition can dilute the concentration of gas reactants in the flame area, and has a certain cooling effect. Filled into the polymer, it helps to form a carbonized layer during combustion, which can not only block the entry of heat and oxygen, but also block the escape of small molecular flammable gases. Of course, the latter two flame retardant effects are much smaller than the former one. They can also effectively slow down the burning speed of the polymer, reduce the amount of smoke produced by combustion, and capture harmful gases.