The four major functions of environmentally friendly flame retardants

Environmentally friendly flame retardants are weapons that prevent fires from occurring, prevent their further spread, and prevent unnecessary losses. Flame retardants have developed rapidly in recent years, with the development of polymer flame retardants being particularly prominent. The development speed is also very fast, which can be divided into halogen flame retardants and halogen-free flame retardants. So, let's take a look at the four major functions of environmentally friendly flame retardants.
1. Environmental flame retardant - cooling effect
Environmentally friendly flame retardants absorb the heat released by plastics during combustion, lower the temperature of burning plastics, prevent their further decomposition, cut off the source of combustible gases, and extinguish flames. For example, organic phosphate nitrogen expansion flame retardant; For example, borax has 10 molecules of crystalline water, which absorbs 141.8 kJ/mol of heat by releasing the crystalline water, thus suppressing the temperature rise of the material through heat absorption and producing a flame retardant effect. The flame retardant effect of hydrated alumina is also due to the endothermic effect brought about by thermal dehydration. In addition, some thermoplastic polymers often produce droplets after decomposition, which can leave the combustion zone and remove reaction heat, thus also having a certain flame retardant effect.
2. Environmentally friendly flame retardants - barrier effect
Non combustible gas or foam layer will be generated during combustion, or liquid or solid coating will be formed, and combustion process will be stopped by oxygen free supplement such as halogen flame retardant, expanded graphite, polyol, polyvinyl alcohol, etc.
The so-called coverage effect refers to the formation of a stable coverage layer at high temperatures, or the decomposition of bubbly substances to cover the surface of polymer materials, so that the heat generated by combustion is difficult to transfer to the interior of the material. The combustible gas generated by thermal decomposition of polymer materials is difficult to escape, and it plays a role in separating the air from the material. Phosphate ester compounds and fire-resistant foam coatings work through this mechanism.
3. Heat dissipation - clearing free radicals
It can eliminate the free radicals o and oh generated by decomposition or pyrolysis during combustion, making the chain reaction in the middle stage of combustion and cutting off the sources of flammable gases such as halogen flame retardants. The combustion of polymers is mainly a free radical chain reaction, and some substances will capture the active intermediates Ho, H, O, HOO, etc. of the combustion reaction, suppress the free radical chain reaction, reduce the combustion rate until the flame is extinguished. Commonly used organic halides such as bromine and chlorine have this inhibitory effect.
4. Anti drip - dilution effect
Releasing inert gas during combustion, diluting the combustible gas and oxygen concentration in the combustion area, can make boron compounds and molybdenum compounds unable to burn.
This type of substance will produce a large amount of non combustible gas when subjected to thermal decomposition. The combustible gas produced by polymer materials and the oxygen in the air cannot reach the combustible concentration range after dilution, preventing polymer materials from catching fire and burning. CO2, NH3, HCl, H2O, etc. can be used as dilution gases. This non combustible gas is generated when heating phosphate amine, chloride amine, carbonate amine, etc.
The above introduces the four major functions of environmentally friendly flame retardants. If you need to learn more, feel free to contact us anytime! Our company has many years of experience and we look forward to your joining at any time.

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