Comparison of the Flame Retardant Properties of Ammonium Polyphosphates with Crystalline Forms II and V

Ammonium polyphosphate have six crystalline forms, of them, form I and form II have industrial uses, their flame retardant properties have been studied extensively. Form V is seldom studied, its flame retardant is not fully known. In this paper, the flame retardant effects of ammonium polyphosphate with crystalline form II (APP-II) and crystalline form V (APP-V) in polypropylene were tested. Results show that the flame retardant effect of APP-V is better than APP-II, and has better mechanical strength that APP-II, meaning it should has a good market perspective in field of halogen-free flame retardation.