The main reason why phosphorus-based flame retardants are not effective when used alone is due to their flame retardant mechanism. The flame-retardant effect of phosphorus-based flame retardants is mainly achieved by promoting dehydration and carbonization of polymer materials during their initial decomposition. This dehydration and carbonization step relies on the oxygen-containing groups of the polymer material itself. For those polymer materials with oxygen-containing groups in their structure, phosphorus-based flame retardants are relatively effective.
However, for materials whose molecular structures do not contain oxygen groups, such as polypropylene, the flame retardant effect is poor when phosphorus-based flame retardants are used alone. This is because the mechanism of phosphorus-based flame retardants relies on the oxygen-containing groups of the material itself, and materials such as polypropylene lack such groups. However, by compounding with other additives such as (OH)3 and Mg(OH)2, a synergistic effect can be produced to improve the flame retardant effect.
Common organophosphorus flame retardants include triphenyl phosphate, tricresyl phosphate, tris(xylene)phosphate, propylbenzene phosphate, butylbenzene phosphate, etc. These phosphate ester flame retardants have dual functions of flame retardancy and plasticization, can achieve halogen-free, and improve flow processability during the plastic molding process while inhibiting residues after combustion and reducing the generation of toxic and corrosive gases.
Although phosphate ester flame retardants have many advantages, such as high efficiency, less impact on light stability, and low corrosiveness during processing and combustion, they also have some disadvantages, such as poor heat resistance, high volatility, and compatibility. Unsatisfactory sex, etc.
On the other hand, phosphorus-containing inorganic flame retardants such as red phosphorus flame retardants, ammonium phosphate salts, ammonium polyphosphates, etc. have the advantages of good thermal stability, non-volatility, no corrosive gas generation, long-lasting effect, and low toxicity. It is widely used in the application of halogen-free flame retardant materials, especially red phosphorus flame retardant, which is favored for its better flame retardant effect.
Generally speaking, the main reason why phosphorus-based flame retardants are not effective when used alone is that their mechanism relies on the oxygen-containing groups of the material itself, and some materials lack such groups. However, through reasonable compounding and synergistic effects, the flame retardant effect can be improved to meet the flame retardant needs of different materials.
