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The principle of flame retardants (2)

Jan 19, 2020

1. Asphyxiation of non-combustible gas

    The flame retardant decomposes non-combustible gas when heated, and dilutes the concentration of combustible gas decomposed by combustibles below the lower combustion limit. At the same time, it also has the effect of diluting the oxygen concentration in the combustion zone, preventing the continuation of combustion and achieving the effect of flame retardancy.

    2. Inhibit chain reaction

According to the chain reaction theory of combustion, it is free radicals that are needed to maintain combustion. The flame retardant can act on the gas-phase combustion zone to capture the free radicals in the combustion reaction, thereby preventing the flame from spreading, reducing the flame density in the combustion zone, and ultimately reducing the combustion reaction rate until it terminates. If the halogen-containing flame retardant, its evaporation temperature and polymer decomposition temperature are the same or similar, when the polymer is thermally decomposed, the flame retardant also volatilizes at the same time. At this time, the halogen-containing flame retardant and the thermal decomposition products are in the gas-phase combustion zone at the same time, and the halogen can capture the free radicals in the combustion reaction, thereby preventing the spread of the flame, reducing the flame density in the combustion zone, and finally reducing the combustion reaction rate until the termination .

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