What are the advantages and disadvantages of the six flame retardants commonly used in nylon modification?

What are the advantages and disadvantages of the six flame retardants commonly used in nylon modification?

1. Brominated styrene polymer

Advantages: Very good thermal stability and because it is melt-mixable with nylon, it has good flowability in the processing process. In addition, the flame-retardant nylon made from it also has excellent electrical properties and good physical and mechanical properties.

Disadvantages: Weak light stability, incompatible with nylon and high cost

2. Decabromodiphenyl ether flame retardant

Advantages: The cost is cheap, so it is most widely used in China, because of its higher bromine content and has a high fire effect on nylon.

Disadvantages: It is a kind of filler-type flame retardant, so it has a greater negative impact on the fluidity of production and processing and the physical and mechanical properties of the product. And its thermal stability and light stability are also weak.

3. Decabromodoxyethane flame retardant

Advantages: Same bromine content and same high fire effectiveness as Decabromodiphenyl ether, and no DPO problems as brominated styrene polymers. It also has good thermal stability and light stability.

Disadvantages: filler-type flame retardants, so the compatibility with polymers is weak, the processing fluidity and physical and mechanical properties of the product are weak. In addition, the cost is higher compared to decabromodiphenyl ether.

 4. Red phosphorus flame retardant

Advantages: the content of available phosphorus is high, under the same flame retardant grade, the amount of addition is lower than that of other flame retardants, so that nylon can well guarantee its own mechanical properties.

Disadvantages: The color of the product is only red, and red phosphorus is easy to burn, and can react with water to form highly toxic phosphine. It is usually only used in nylon  (Microencapsulating or masterbatching common red phosphorus can circumvent its deficiencies.) )

 5. Ammonium polyphosphate (APP) flame retardant ammonium polyphosphate (APP) uses to reduce the degradation temperature of nylon, change the composition of the final gas phase product to participate in the thermal degradation of nylon, and produce a honeycomb carbonization overlay on the polymer matrix, which isolates the heat and material transfer at the interface of the two phases, and plays the function of guaranteeing the matrix. Because the charcoal has a tendency to flow, the substrate under the carbon layer will be exposed, which will increase the risk of combustion. Add some inorganic additives, such as talc (Talc), MnO2, ZnCO3, CaCO3, Fe2O3, FeO, Al(OH)3, etc., to improve the fire protection effect. Add the above additives (1.5%~3.0%) to nylon 6 with ammonium polyphosphate (APP) addition amount of 20%, and the LOI value can be increased to 35%~47%, achieving V-0 grade.

 6. Nitrogen-based flame retardants (MCA, MPP, etc.)

Advantages: Nitrogen-based flame retardants suitable for nylon are mainly MCA (melamine cyanurate), MPP (melamine polyphosphate) and so on. Regarding its fire prevention principle, the first is the physical fire prevention method of “sublimation heat absorption”, that is, the use of the “sublimation heat absorption” of flame retardants to reduce the surface temperature of polymer materials and isolate air to achieve the purpose of fire prevention, followed by the principle of direct carbonization expansion catalyzed by flame retardants and nylon in the condensed phase. Advantages: nitrogen-based flame retardants are slightly toxic, non-corrosive, relatively stable to heat and ultraviolet rays, good fire prevention effect and cheap.

Disadvantages: its fireproof plastic processing is inconvenient, the dispersion in the substrate is weak, the thermal stability is poor, and the electrical properties of the product are weak in a humid environment because it is susceptible to moisture.


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Post time: Nov-22-2022