The Study on Aging and Degradation Mechanism of Ammonium Polyphosphate in Artificial Accelerated Aging

The effect of thermal and oxygen aging on degradation of ammonium polyphosphate was studied, two brands of ammonium polyphosphate was processed with artificial accelerated aging. The structural changes of ammonium polyphosphate in laboratory accelerated thermal aging were characterized by Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance. The results show that ammonium polyphosphate is converted into ammonium dihydrogen phosphate by thermal aging. During the process, the P=O bonds increase, the P-O-P bonds break, and the average degree of polymerization decreases. The results of study put forward new requirements for durability of ammonium polyphosphate used in flame retardant.