AMMONIUM POLYPHOSPHATE

CAS NUMBER: 68333-79-9

EC NUMBER: 269-789-9

DESCRIPTION:

Ammonium polyphosphate is an inorganic salt of polyphosphoric acid and ammonia. 
The chain length (n) of this polymeric compound is both variable and branched, and can be greater than 1 000. 
Short and linear chain Ammonium polyphosphate (n < 100) are more water sensitive (hydrolysis) and less thermally stable than longer chain APPs (n >1000), which show a very low water solubility (< 0.1 g/ 100 ml).
Ammonium polyphosphate is a stable, non-volatile compound. 
In contact with water Ammonium polyphosphate it slowly gets hydrolysed to monoammonium phosphate (orthophosphate). 

Higher temperatures and prolonged exposure to water will accelerate the hydrolysis. 
Long chain Ammonium polyphosphate starts to decompose at temperatures above 300 °C to polyphosphoric acid and ammonia. 
Short chain Ammonium polyphosphate will begin to decompose at temperatures above 150 °C.
Ammonium polyphosphate is an inorganic salt of polyphosphoric acid and ammonia containing both chains and possibly branching. 

Ammonium polyphosphate's chemical formula is [NH4 PO3]n(OH)2 showing that each monomer consists of an orthophosphate radical of a phosphorus atom with three oxygens and one negative charge neutralized by an ammonium cation leaving two bonds free to polymerize. 
In the branched cases some monomers are missing the ammonium anion and instead link to three other monomers.
The properties of ammonium polyphosphate depend on the number of monomers in each molecule and to a degree on how often it branches. 
Ammonium polyphosphate can be prepared by reacting concentrated phosphoric acid with ammonia. 
However, iron and aluminum impurities, soluble in concentrated phosphoric acid, form gelatinous precipitates or "sludges" in ammonium polyphosphate at pH between 5 and 7.
Other metal impurities such as copper, chromium, magnesium, and zinc form granular precipitates.

However, depending on the degree of polymerization, ammonium polyphosphate can act as a chelating agent to keep certain metal ions dissolved in solution.
Ammonium polyphosphate is used as a food additive, emulsifier, and as a fertilizer.
Ammonium polyphosphate is also used as a flame retardant in many applications such as paints and coatings, and in a variety of polymers: the most important ones are polyolefins, and particularly polypropylene, where APP is part of intumescent systems.
Compounding with Ammonium polyphosphate-based flame retardants in polypropylene is described in.
Further applications are thermosets, where APP is used in unsaturated polyesters and gel coats (APP blends with synergists), epoxies and polyurethane castings (intumescent systems). 

Ammonium polyphosphate is also applied to flame retard polyurethane foams.
Ammonium polyphosphates as used as flame retardants in polymers have long chains and a specific crystallinity. 
They start to decompose at 240 °C to form ammonia and phosphoric acid. 
Ammonium polyphosphate acts as an acid catalyst in the dehydration of carbon-based poly-alcohols, such as cellulose in wood. 
Ammonium polyphosphate reacts with alcohol groups to form heat-unstable phosphate esters. 

The esters decompose to release carbon dioxide and regenerate the phosphoric acid catalyst.
In the gas phase, the release of non-flammable carbon dioxide helps to dilute the oxygen of the air and flammable decomposition products of the material that is burning. 
In the condensed phase, the resultant carbonaceous char helps to shield the underlying polymer from attack by oxygen and radiant heat.
Use as an intumescent is achieved when combined with starch-based materials such as pentaerythritol and melamine as expanding agents. 
The mechanisms of intumescence and the mode of action of APP are described in a series of publications.

Ammonium polyphosphate is a branched or linear polymeric compound with a variable degree of polymerization (n). 
Generally, Ammonium polyphosphate of a low degree of polymerization (n ≤ 100, crystalline form I) is water soluble or water sensitive, while APP with longer chains (n ≥ 1000, crystalline form II) displays a very low water solubility (<0.1 g/100 mL). 
In general, long-chain APP starts to degrade at a temperature of above 300°C, generating ammonia and polyphosphoric acid, while the short-chain one begins decomposing at 150°C. 
Thus choosing Ammonium polyphosphate as the flame retardant strongly depends on the processing temperature of materials. 
When Ammonium polyphosphate is added into a polymeric material containing oxygen and/or nitrogen elements, the char may form. 

At high temperature, Ammonium polyphosphate degrades to create free acidic hydroxyl groups and form ultraphosphate and polyphosphoric acid, which can catalyze the dehydration reaction of polymers to yield char residues. 
Ammonium polyphosphate is an inorganic salt of polyphosphoric acid and ammonia containing both chains and possibly branching. 
The properties of Ammonium polyphosphate depend on the number of monomers in each molecule and to a degree on how often it branches. 
Shorter chains (n < 100) are more water sensitive and less thermally stable than longer chains (n > 1000).
Consequently, short polymer chains and oligomers (e.g. pyro-, tripoly-, and tetrapoly-) are more soluble and show decreasing solubility with increasing chain length.

Ammonium polyphosphate is used as a flame retardant in many applications such as paints and coatings, and in a variety of polymers: the most important ones are polyolefins, and particularly polypropylene, where APP is part of intumescent systems.
Compounding with Ammonium polyphosphate-based flame retardants in polypropylene is described in.
Further applications are thermosets, where APP is used in unsaturated polyesters and gel coats (APP blends with synergists), epoxies and polyurethane castings (intumescent systems).
Ammonium polyphosphates as used as flame retardants in polymers have long chains and a specific crystallinity. 
They start to decompose at 240 °C to form ammonia and polyphosphoric acid. 

Ammonium polyphosphate acts as a catalyst in the dehydration of carbon-based poly-alcohols, such as cellulose in wood. 
Ammonium polyphosphate reacts with alcohol groups to form heat-unstable phosphate esters. 
The esters decompose to release carbon dioxide and regenerate the phosphoric acid catalyst. 
In the gas phase, the release of non-flammable carbon dioxide helps to dilute the oxygen of the air and flammable decomposition products of the material that is burning. In the condensed phase, the resultant carbonaceous char helps to shield the underlying polymer from attack by oxygen and radiant heat therefore preventing the pyrolysis of the substrate.
Use as an intumescent is achieved when combined with polyalcohols such as pentaerythritol and melamine as expanding agent. 

The mechanisms of intumescence and the mode of action of APP are described in a series of publications.
Due to its uncritical toxicological and environmental profile, ammonium polyphosphate has the potential to widely substitute halogen-containing flame retardants in a series of applications like flexible and rigid PUR-foam and thermoplastics.
As the basis of our Exolit® AP products, it can provide non-toxic fire safety properties to flame retardant and fire-resistant intumescent coatings as well as to other products.
Ammonium polyphosphate is an environment-friendly and halogen-free flame retardant. 

Ammonium polyphosphate is the main constituent of many intumescent flame retardant systems: coatings, paints and engineering plastics.
For the chemical point of view, Ammonium polyphosphate is an inorganic salt of polyphosphoric acid and ammonia. 
Ammonium Polyphosphate is an environment-friendly, non-toxic, halogen-free flame retardant, chemically Ammonium Polyphosphate is an organic salt of polyphosphoric acid and ammonia.
Ammonium polyphosphate is a stable and non-volatile compound. It comes under the category of halogen free flame retardants and works as a smoke suppressant too. 
Ammonium polyphosphate is very cost effective when compared to other halogen free systems. 

Lower loading into polymers ensures good retention of mechanical and electrical properties and excellent flow.  
Allowing plastics to exhibit excellent processability, Ammonium Polyphosphate (APP) is used as an efficient flame retardant in the furniture industry and for interior fabrics for the automotive industry.
Ammonium polyphosphate is used as a flame retardant in many applications such as paints and coatings, and in a variety of polymers: the most important ones are polyolefins, and particularly polypropylene. 
Further applications are thermosets, where Ammonium polyphosphate is used in unsaturated polyesters and gel coats, epoxies and polyurethane castings. 

Ammonium polyphosphate is also applied to flame retard polyurethane foams.
Ammonium polyphosphate is usually synthesized by heating diammonium hydrogen phosphate and phosphorus pentaoxide at ammonia atmosphere, in which phosphorus pentaoxide is used as condensing agent. 
Ammonium polyphosphate is manufactured by mixing together ammonium phosphate and urea in a molten condition. 
Considerable heat is generated which transform the ammonium phosphate to the molten state. 

Ammonium polyphosphate includes a group of nitrogen phosphorus materials: mono ammonium phosphates and diammonium phosphates, mixtures of the two or combinations with ammonium nitrate or ammonium sulfate.
Ammonium polyphosphate is an organic salt of polyphosphoric acid and ammonia. 
As a chemical, Ammonium polyphosphate is non-toxic, environmentally friendly and halogen-free. 
Ammonium polyphosphate is most commonly used as a flame retardant, selection of the specific grade of ammonium polyphosphate can be  determined by the solubility, Phosphorus content, chain length and polymerization degree.

APPLICATION:

-Widely used in water soluble fire-retardant coating
-Can be applied by spray, dip, or pressure treatment
-Aqueous solution used in the fire-retardant treatment for wood (i.e. corrugated board, kraft paper), paper, textile, and fibers

CHEMICAL PROPERTIES:

-Appearance: white powder or lumps
-P2O5 (%) w/w: ≥ 46
-N (%) w/w: ≥ 24
-Solubility g/100ml H20, 25°C: ≥ 80
-pH value (1% water solution): 6.5 - 8.5
-Water Insoluble (25°C) (%): 0.02

PROPERTIES:

-Appearance: White free-flowing powder
-Whiteness: 92.0 Min
-pH (10% slurry -25°C): 5.5-7.5
-Acid Value, KOH mg/1g: 1.0 Max
-Solubility in water (25°C), g/100ml H2O: 0.50 Max
-Nitrogen, w/w%: 14.0-15.0
-Phosphorus (P), w/w%: 31.0-32.0
-Thermal decomposition onset, °C: 285 Min
-Average Particle Size, D50, µm: About 15

TECHNICAL INFORMATION:

-Physical State: Solid
-Storage: Store at room temperature
-Melting Point: >360° C

PROPERTIES:

-(NH4)3PO4: Ammonium phosphate
-Density: 1.619 g/cubic cm
-Molecular Weight/ Molar Mass: 149.09 g/mol
-Boiling Point: 130°C
-Melting Point: 155 °C (311 °F; 428 K) decomposes
-Chemical Formula: H9N2O4P

PHYSICAL PROPERTIES:

-Odour: Ammonia odour
-Appearance: White, tetrahedral crystals
-Complexity: 6.5
-Covalently-Bonded Unit: 3
-Hydrogen Bond Donor: 3
-Solubility: Readily soluble in water
-Solubility pH: 4 to 4.5

USES:

-Ammonium polyphosphate is a broad generic name for a variety of fertilizer materials containing both nitrogen and phosphate.
-Ammonium polyphosphates are becoming increasingly important as a source of available P2O5. P2O5 is somewhat higher in ammonium phosphates than in triple superphosphate.
-Mainly Ammonium polyphosphate is used as a solid fertilizer but can also be utilized in solution.
-Ammonium polyphosphate is used as components of intumescent paints and mastics where they function as an acid catalyst.
-Used in paints in which pentaerythritol is the carbonific component and melamine is the specific compound.
-Ammonium polyphosphate is a specialty chemical that finds many different uses in key industries.  
-Ammonium Polyphosphate, is an environment-friendly and halogen-free flame retardant. 
-Ammonium polyphosphate is the main constituent of many intumescent flame retardant systems: coatings, paints and engineering plastics. 
-Ammonium polyphosphate is used to prepare 20% Phosphorous/Nitrogen containing flame retardants, it can be used solely or in conjunction with other materials in the flameproof treatment for textiles, papers, fibers and woods. 
-Special treatment can be used to prepare 50% high concentration flameproof formulations required for special applications.
-The most common ammonium polyphosphate fertilizers have a N-P2O5-K2O (nitrogen, phosphorus and potassium) composition of 10-34-0 or 11-37-0. 
-Polyphosphate fertilizers offer the advantage of a high nutrient content in a clear, crystal-free fluid that remains stable within a wide temperature range and stores well for long periods. 
-A variety of other nutrients mix well with polyphosphate fertilizers, making them excellent carriers of micronutrients typically needed by plants.

STORAGE:

-Store in its unopened pacakaging
-Keep it tightly closed when not in use
-Keep away from sunlight 

SYNONYM:

Ammonium phosphate, tribasic
Triammonium orthophosphate
triazanium;phosphate
Phosphoric acid, triammonium salt
UNII-2ZJF06M0I9
2ZJF06M0I9
Ammonium polyphosphate, Degree of Polymerization: >1000
triazanium phosphate
triammonium phosphate
Ammonium phosphate tribasic
Ammonium acid phosphate
DTXSID8052778
Phosphoric acid, di-C4-18-alkyl esters, ammonium salts