Effect of high temperature resistant flame retardant

The high-temperature flame retardant is a functional additive that gives the flammability of flammable polymers. It is mainly designed for the flame retardant planning of polymer materials. It exerts its flame retardant effect through several mechanisms, such as heat absorption, masking, chain reaction, and suffocation effect of non combustible gases. Most flame retardants achieve flame retardancy through several mechanisms. Today, let's learn about the effect of high-temperature flame retardant.

Effect of flame retardant

1. Heat absorption effect

The heat released by any incineration in a short time is limited. If part of the heat released by the fire source can be absorbed in a short time, the flame temperature will be reduced, the heat radiated to the surface of the combustibles and the effect of cracking the vaporized combustible molecules into free radicals will be reduced, and the incineration response will be suppressed to a certain extent. Under high temperature conditions, the flame retardant has a strong endothermic reaction, absorbs part of the heat released by incineration, reduces the temperature of the surface of combustibles, effectively suppresses the generation of combustible gases, and hinders the spread of incineration. The flame retardant mechanism of Al (OH) 3 flame retardant is to increase the heat capacity of the polymer, make it absorb more heat before reaching the thermal differentiation temperature, and then improve its flame retardant performance. This kind of flame retardant gives full play to its large amount of heat absorption when it combines with water vapor, and improves its own flame retardancy.

2. Masking effect

After the flame retardant is added to the combustible materials, the flame retardant can form a glass like or stable foam cover layer at high temperature, isolate oxygen, have the effect of heat insulation, oxygen insulation and preventing the combustible gas from escaping outward, and then achieve the purpose of flame retardation. For example, when organophosphorus flame retardants are heated, cross-linked solid substances or carbonized layers with more stable structures can occur. On the one hand, the composition of the carbonized layer can prevent the further pyrolysis of the polymer, on the other hand, it can prevent the thermal differentiation products from entering the gas phase to participate in the incineration process.

3. Reaction of the control chain

According to the chain reaction theory of incineration, free radicals are required to maintain incineration. The flame retardant can act on the gas phase incineration area, capture the free radicals in the incineration reaction, then block the propagation of the flame, reduce the flame density in the incineration area, and finally reduce the incineration reaction speed until the end. For example, the evaporation temperature of halogen-containing flame retardant is the same as or near the polymer differentiation temperature. When the polymer is heated and differentiated, the flame retardant will also evaporate out. At this moment, halogen-containing flame retardants and thermal differentiation products are in the gas-phase incineration area, so halogen can capture free radicals in the incineration reaction and interfere with the chain reaction of incineration.