ABSTRACT Polypropylene (PP) is widely used in automotive and other fields with high fire safety requirements due to its low density, low cost, and excellent processing properties. However, as a typical hydrocarbon polymer, PP is inherently flammable, exhibits a high heat‐release rate, and is prone to melt dripping accompanied by smoke generation during combustion, which severely limits its broader use in high fire‐safety applications. This review systematically summarizes recent advances in flame‐retardant PP, with particular emphasis on the flame‐retardant mechanisms and performance characteristics of metal hydroxides, phosphorus‐based and phosphorus–nitrogen flame retardants (FRs), intumescent FRs, nanoparticles, and bio‐based FRs in PP matrices. By comparatively analyzing flame‐retardant efficiency, additive loading, and changes in mechanical properties, the trade‐offs between enhanced fire performance and mechanical property retention associated with different flame‐retardant strategies are elucidated. Finally, in light of the practical requirements for fire safety and overall performance in automotive applications, synergistic design strategies and future development directions for flame‐retardant PP are discussed.
Hu et al. (Sun,) studied this question.