Combustion requires three main elements-combustibles, combustion aids (oxygen) and a source of ignition. The process of combustion is divided into heating, decomposition, fire, burning and spreading. If you remove any of these elements, or find a way to control the combustion process in the embryonic stage of heating and decomposition, you can effectively avoid the occurrence of fire. Here to introduceflame retardantThe principle of, I hope to help everyone.

In terms of preventing flame combustion, different types of flame retardants have their own tricks: some prevent combustibles from generating combustible gases by absorbing heat; Some form a dense covering layer on the surface of combustibles to isolate combustibles from contacting oxygen. Some capture free radicals involved in the combustion reaction to achieve the purpose of inhibiting the chain reaction of free radicals. The other is to slow down the combustion speed by generating incombustible gas to dilute oxygen.

Inorganic flame retardant Al(OH)3 in the heat up to 200 ℃ will be decomposed, the release of crystal water, crystal water heat evaporation into water vapor. This series of processes will absorb a large amount of heat, reduce the temperature of the material surface and flame zone, and slow down the rate of thermal cracking reaction. In addition, the water vapor produced by the crystal water can also reduce the oxygen concentration, further inhibiting the spread of fire.

Phosphorus flame retardant heated into a more stable structure of the cross-linked solid matter or carbonized layer, like a layer of solid armor, the combustible material wrapped up, both to prevent further pyrolysis of the material, but also to prevent the internal decomposition of the combustible gas overflow to continue burning.

The evaporation temperature of the bromine flame retardant is the same as or similar to the decomposition temperature of the polymer material. When the polymer material is decomposed by heat, the bromine flame retardant will also volatilize and enter the gas phase combustion zone at the same time as the thermal decomposition product. The flame retardant can quickly capture the free radicals in the gas phase combustion zone, inhibit the free radical chain reaction, prevent the flame propagation, and finally slow down the combustion reaction rate until the end.