With the development of the polymer material industry, synthetic materials such as plastics, rubber, and fibers are more and more widely used in construction, chemical, military, and transportation fields. Due to the flammability of polymer materials, its flame retardant technology has received global attention. With the increasing environmental awareness of various countries and the promulgation of flame retardant regulations, the flame retardant market has developed rapidly. Currently widely used flame retardants are halogen (mainly chlorine and bromine), phosphorus (including halogen-phosphorus) and inorganic flame retardants [mainly Mg (OH) 2 and Al (OH) 3] . Halogen-based flame retardants (especially bromine-based) and phosphorus-based flame retardants have good flame retardant effects, but they are expensive and have environmental problems, so their use is restricted. Therefore, inorganic flame retardants such as magnesium hydroxide and aluminum hydroxide with high efficiency, strong smoke suppression performance, non-toxic and harmless are more and more favored by users.
In addition to having a considerable impact on the environment, magnesium hydroxide is compared with aluminum hydroxide in terms of thermal reaction, decomposition temperature, applicable polymer, flame retardant ability, smoke suppression ability, acid stability, etc. Flame retardants are superior to aluminum hydroxide flame retardants, and also superior to traditional halogen and phosphorus flame retardants.