Flame retardant treatments for polypropylene: Strategies and recent advances

Polypropylene (PP), one of five general-purpose plastics, is widely used in many fields. However, the intrinsic alkane structure of PP makes it relatively easy to burn, leading to limiting its scope of application. Here, this article reviews the most commonly flame retarding strategies used in PP matrices, including the flame-retardant compounds, application methods as well as flame-inhibition mechanism and also focuses on recent advances and foresees the future outlook of such applications. It is seen that traditional flame retardants and some new compounds are considered in modifying the fire behaviors of PP. At present, with the enhancement of environmental awareness, the application frequency of novel materials in this field is increasing. Thus, the harmonious combination of traditional flame retardants with the newly derived flame retardants has broadened the choice of researchers to come up with novel strategies for improving the fire performance of PP matrices.