Study on the Hydrophobic Modification of Ammonium Polyphosphate and its Application in Flame Retardant Polypropylene

Abstract

In this paper, ammonium polyphosphate (APP) was modified by methyl hydrogen silicone oil and gas hydrophobic silica, hydrophobic ammonium polyphosphate (HAPP) was prepared. Then, HAPP was separately mixed with starch and melamine were introduced into polypropylene as flame retardants to prepare polypropylene (PP) retardant materials. The hydrophobic retention was of HAPP above 90%. According to the results from testing its wettability, its contact angle was 140.69°, which was increased by about 120°compared with APP, and this indicated the HAPP had better hydrophobic properties than that of the unmodified. And a comprehensive analysis is conducted on the scanning electron microscope (SEM) and infrared spectroscopy (FTIR).The results showed that the surface of APP is coated with methyl hydrogen silicone fluid and gas hydrophobic silica. The limited oxygen index (LOI) of the flame retardant PP material is measured by the oxygen index tester, and at a total flame retardant loading of 33wt%, the LOI value of PP retardant materials can achieve 29%, indicating that this flame retardant can better make the PP into the stable charred layer, and improve the performance of the flame retardant PP material greatly.