The flame retardant mechanism of magnesium hydroxide

Messi Biology said that the main varieties of inorganic flame retardants are magnesium hydroxide, aluminum hydroxide, tin oxide, antimony oxide, molybdenum oxide, red phosphorus, zinc borate, ammonium molybdate and so on. Among them, magnesium hydroxide and aluminum hydroxide because of the decomposition of heat absorption, and the generated water can play a role in isolating the air, the decomposition of the generated oxide and high temperature resistant substances, so magnesium hydroxide and aluminum hydroxide these two flame retardants can play a role in addition to flame retardant, but also fill the role, and does not produce corrosive halogen gas and harmful gases, smokeless, non-toxic, non-drip, non-volatile, long-lasting effect, etc. Features.

At present, the amount of domestic aluminum hydroxide is relatively large, but with the increase of polymer processing temperature, aluminum hydroxide is easy to decompose, reducing the flame retardant effect. Therefore, magnesium hydroxide is gradually replacing aluminum hydroxide. Compared with aluminum hydroxide, magnesium hydroxide has the following advantages.


The decomposition temperature of magnesium hydroxide is 100℃ higher than that of aluminum hydroxide, reaching 330℃, which is more helpful to increase the processing temperature of plastics, speed up the extrusion speed and shorten the molding time; the high decomposition energy of magnesium hydroxide helps to absorb the combustion heat and improve the flame retardant efficiency; the neutralization ability of magnesium hydroxide and acid is strong, which can neutralize the acidic gas CO2, SO2, NOX, etc. produced by plastics in the combustion process more quickly;


When magnesium hydroxide is heated at 340℃-490℃, it will decompose and absorb the heat on the surface of the combustion material, thus playing the role of flame retardant. At the same time, it will release a large amount of water to dilute the oxygen on the surface of the combustible material, the decomposition of the generated active magnesium oxide will adhere to the surface of the combustible material to further prevent the combustion process.

Secondly, magnesium hydroxide in the whole process of flame retardant not only will not produce any harmful substances, and magnesium hydroxide decomposition products in the flame retardant effect, but also can absorb a large number of plastics, rubber and other polymer combustion smoke and harmful gases, active magnesium oxide can continue to absorb the molten residue of incomplete combustion, and then make the burning soon stop, and eliminate smoke and stop molten droplets, is an emerging It is an emerging environmentally friendly inorganic flame retardant.

Leave a Comment

Your email address will not be published. Required fields are marked *