Recent Research Progress on the Flame-Retardant Mechanism of Halogen-Free Flame Retardant Polypropylene

Polypropylene (PP) is one of the five kinds of universal polymers that have greatly improved our life qualities. While a pestilent limitation of PP is its flammability. Usually, halogen-containing flame retardants (FRs) are used to improve its flame retard ability. However, the halogen-containing FRs are limited more and more strictly because they would produce environment problems, such as the release of corrosiveness smoke and toxicity combustion products. Hence, the researches of halogen-free FRs to replace the halogen-containing FRs become hot topics. In this article, the recent research progress of halogen-free FRs as additives for polypropylene and the flame retardant mechanism of halogen-free FRs are reviewed.