Polypropylene is one of the five general plastics

which has a good comprehensive performance. However

its poor flame retardancy restricts its further applications. As a type of environmentally friendly inorganic flame retardnant

magnesium hydroxide (MH) is extensively applied in flame retardant polypropylene

but the strongly polar MH flame retardant leads to the poor compatibility between MH particles and the polymer matrix

as well as the poor dispersion of MH in polymer matrix

which not only results in the low flame retardant efficiency

but also brings severe negative influences to the mechanical properties of composites. To Improve the interface compatibility between flame retardant particles and polymer matrix

it is essential to change the surface performance of filler. This paper presents a summary of the main advances in different methods of surface modification for MH in flame retardant polypropylene in recent years

including the surface chemical modification

surface grafting modification and microencapsulation. The trends of future developments of the surface modification of MH in flame retardant polypropylene composites have been proposed based on this view.