Halogen-phosphorus flame retardant synergistic effect

Halogen-phosphorus flame retardant synergistic effect

The combined use of halogen flame retardant and phosphorous flame retardant can produce a significant flame retardant effect. For halogen - phosphorus flame retardant synergistic effect, people put forward halide - phosphorus cooperate to use can promote each other, and form stronger than used alone with flame retardant effect of halogen - phosphorus compounds and their transformations PBr3, PBr, POBr3, etc.

Application of pyrolysis gas chromatography, differential thermal analysis, differential scanning calorimetry analysis, determination of oxygen index, flame retardant, temperature programmed observation and other methods to the research of halogen - phosphorus flame retardant synergistic effect shows that the halogen - phosphorus flame retardant when used decomposition temperature slightly lower than when used alone, very intense and decomposition, combustion zone, chlorine and phosphorus compounds hydrolyzate formation of the flue gas clouds can stay longer in the combustion zone, formed a powerful air interval of abscission layer.

About halogen - phosphorus flame retardant synergistic interaction mechanism of the effect of not enough perfect, it is generally believed with nitride (such as urine, melamine, guanidine, dicyandiamide, methylol melamine, etc.) can promote the phosphate phosphorus acylation reaction with cellulose. The formation of phosphoric acid is much easier to produce the ester reaction, and the thermal stability of the ester is better than that of phosphate.

The synergistic flame retardant effect of phospho-nitrogen flame retardant can promote the formation of coke and water at lower temperature and increase the production of coke residue, thus improving the effect of flame retardant. The phosphating and nitrides form an expanded coking layer at high temperature, which ACTS as a protective layer for the insulation resistance, and nitrogen compounds play the role of foaming agent and coke enhancer.

Basic element analysis, the residue containing nitrogen, phosphorus and oxygen three elements, they are formed under the flame temperature thermal stability of amorphous material, like vitreous body, as a thermal insulation layer of fiber.
Antimony trioxide cannot be used as a flame retardant (except for halogenated polymers), but it has a great synergistic effect with halogen flame retardants.

Because of the presence of antimony trioxide in halide, burns the generated SbCl3, SbBr3 antimony halide, such as the relative density is very large, covering the polymer surface covering effect, and also have to capture the role of free radicals in the gaseous state. For example, antimony trioxide and chlorine flame retardants and, due to chloride heat decomposition hydrogen chloride, hydrochloric acid and antimony trioxide reaction to generate chlorine antimony oxide, antimony trichloride and antimony oxychloride thermal decomposition continue to generate antimony trichloride.

The combination of hydrated zinc borate and halogen flame retardants has a good synergistic effect. Under combustion conditions, they and their pyrolysis products interact with each other so that all flame retardant elements can be used as flame retardants. Hydration reaction with phosphorus-containing flame retardant zinc borate generated three dihalide zinc and boron halide, they can capture, HO, h. in gas phase, formed in the solid phase vitreous isolation layer, heat insulation, oxygen, water dilute oxygen burning zone and take away the heat generated, so can play a larger flame retardant effect.



Triethyl phosphate (TEP)

Triethyl phosphate(Flame retardants TEP) is mainly used as the high boiling point solvents,catalysts, plasticizers, flame retardants, ethylating agent, and organic peroxide stabilizer. And Triethyl phosphate(TEP) is widely used in medicine, pesticides, vinyl ketone, resins, hydraulic oil and other production areas. In Japan, 70% of this product is used in catalyst.


The thermal stability of ammonium salts is poor, and ammonia is released when heated, such as (NH4) 2SO4, and its decomposition process is as follows: [NH4] 2SO4, NH4HSO4, H2SO4, 10 NH3 up

The release of ammonia gas is a gas that dilutes the oxygen in the air. The formation of H2SO4 ACTS as the catalyst for dehydrating carbonization. Other experiments indicate that NH3 also has the following reactions in the fire: NH3 +O2 - N2+ H2O. Besides, the N2O4 of the deep oxidation product is accompanied by the N2O4, which shows that the NH3 has not only physical flame retardation, but also chemical flame retardation.

Nanocomposite materials are separately mentioned, although they are all compound flame retardant, but their principle is a little different. Nanocomposites refer to the study of one or more components in a material that are dispersed in a different component base in a nanoscale or molecular level. This study is only a decade old. Experiments show that exist in the size of the ultrafine nanomaterials, so the performance of the various types of nanocomposites than its corresponding macro or micro level have significant improvement, composite material of the thermal stability and flame retardant properties will be significantly improved.

Some flaky mineral can in physics and chemistry cracked into nanoscale structures under the action of micro area, generally in a fraction of the lamella spacing to several nanometers, they can not only make some polymer intercalated into the nano

Size of interlayer space, form "intercalated nanocomposites", and the inorganic polymer sandwich will be open to form single laminar inorganic length to diameter ratio is very big, evenly dispersed in polymer matrix, the form is "type nanocomposites layer". Using the properties of porous or layered inorganic compounds, preparation of inorganic/polymer nanocomposites, in the process of pyrolysis and combustion, carbon and inorganic salt multilayer structure can be formed, have the effect of heat insulation and prevent flammable gas to escape, to flame retardant polymers. In addition, inorganic/polymer nanocomposites can also be used for anticorrosion, seepage prevention and wear resistance. Is currently in nylon/clay nanocomposites, PS/clay nanocomposites, PET/clay nanocomposites, PBT/clay nanocomposites, nano composite material such as PP/clay nanocomposites research has made gratifying achievements.

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