In life, few people should have heard of Ammonium polyphosphate (APP) this thing, it is abbreviated as the APP. Ammonium phosphate(APP) is a inorganic salt made up of polyphosphate and ammonia. The chain length of this polymer compound is both variable and branched, and can be greater than 1000. Short-chain and linear chain Apps are more sensitive and have lower thermal stability than long-chain Apps, which show very low water solubility.

Optical APP is a stable, non-volatile compound. When in contact with the water APP, it is slowly hydrolyzed into ammonium phosphate. Higher temperatures and prolonged water exposure can accelerate hydrolysis. The long chain APP begins to decompose into polyphosphate and ammonia at temperatures above 300°c. The short-chain APP will begin to decompose at temperatures above the temp.

Ammonium polyphosphate(APP) can also be used as flame retardants for many applications, such as paints and coatings, as well as a variety of polymers: the most important is polyolefin, especially polypropylene, where the application is part of the expansion system. With the description of application-based flame retardant composites in polypropylene, further applications include the application of thermosetting, unsaturated polyester and gel coatings, epoxy resins and polyurethane castings. APP are also suitable for flame-retardant polyurethane foams.