The main role of environmental flame retardant in fire

2022-08-10 16:58:54

As we all know, environmental protection flame retardant is a kind of flame retardant. Environmental protection flame retardant is a composite material based on resin and rubber. It is an additive that can prevent polymer materials from igniting or inhibiting flame propagation. Among them, the commonly used environmental flame retardants are compounds of phosphorus, bromine, chlorine, antimony and aluminum. The following editor will take you to understand how environmental flame retardants are flame retardant in fire.

Environmental friendly flame retardants play three major roles in fire:

1. Covering effect.

After adding environment-friendly flame retardant to combustible materials, glass like or stable foam covering layer can be formed under high temperature to isolate oxygen, which has the functions of heat insulation, oxygen isolation and preventing combustible gas from escaping outward, so as to achieve the purpose of flame retardation. The reason is that on the one hand, it can prevent the polymer from further pyrolysis, and on the other hand, it can prevent the internal thermal decomposition products from entering the gas phase to participate in the combustion process.

2. Inhibiting chain reaction.

According to the chain reaction theory of combustion, free radicals are needed to maintain combustion. Environmental friendly flame retardant can act on the gas phase combustion zone, prevent the propagation of flame, reduce the flame density in the combustion zone, and reduce the combustion reaction speed until the end. For example, the evaporation temperature of halogen-containing flame retardant is the same or similar to the decomposition temperature of polymer. When the polymer is decomposed by heat, the flame retardant also volatilizes. It can capture the free radicals in the combustion reaction, thus preventing the propagation of flame, reducing the flame density in the combustion zone, and finally reducing the combustion reaction speed until the end.

3. Asphyxiating effect of incombustible gas.

When the environmental protection flame retardant is heated, it will decompose the gas that is not conducive to combustion, dilute the concentration of the combustible gas below the lower limit of combustion, dilute the oxygen concentration in the combustion zone, prevent the combustion from continuing, and thus achieve the flame retardant effect.