Because polymer synthetic materials are flammable and flammable, they bring great safety risks to people's lives. Therefore, in order to reduce the harm of such materials, flame retardants and flame retardant materials have gradually attracted people's attention. The traditional halogen and halogen series flame retardant preparation methods are relatively mature. However, the environmental pollution caused by halogen flame retardants cannot be underestimated. Especially this year, people's awareness of environmental protection has gradually deepened. The development prospect of the agent is relatively optimistic, and has gradually become a hot spot in the field of flame retardants. Magnesium hydroxide has become a new type of flame retardant that combines cooling, cooling and flame retardant from its own non-toxic and harmless physical properties.
Magnesium hydroxide flame retardant is a kind of inorganic flame retardant for polymer matrix composites with good application prospects. Like aluminum hydroxide, magnesium hydroxide flame retardants rely on chemical decomposition to absorb heat and release water when heated to play a flame retardant role. Therefore, it has non-toxic, low smoke, and magnesium oxide formed after decomposition is chemically stable. Produce secondary pollution and other advantages. However, compared with halogen-containing organic flame retardants, in order to achieve a considerable flame retardant effect, the filling amount should generally reach more than 50%. Because magnesium hydroxide is an inorganic substance, the compatibility between the surface and the polymer base material is poor. Such a high filling amount, if it is not subjected to surface modification treatment, after filling into the polymer material, it will lead to composite materials The mechanical properties are reduced. Therefore, it must be surface-modified to improve its compatibility with the polymer base material, so that the mechanical properties of the filler material do not drop, and even the mechanical properties of the material are improved.
As an important chemical product, magnesium hydroxide micro-nano materials have been widely used in ceramics, flame retardant, catalysis, medicine and environmental protection. The morphology, size, and dispersibility of magnesium hydroxide micro / nano materials will affect their application performance, so they need to be regulated. In the following, magnesium hydroxide is used as the research object, and the morphology, size and dispersibility of magnesium hydroxide products are successfully controlled by adjusting the synthesis conditions. Using magnesium hydroxide powder as one of the starting materials, an aluminum-magnesium composite coating was prepared by plasma spraying technology.
A process for preparing magnesium hydroxide micro-nano powders by ammonia diffusion method at room temperature was designed. Under the guidance of S042- ion and additive PEG, magnesium hydroxide micro-nanoparticles can crystallize into spherical crystals with good morphology. The effects of reaction concentration, reaction time, solvent and additives on the final morphology of the spherical product were studied through different comparative experiments. By changing the type of additives, the average diameter of the spherical crystals can be adjusted to meet the requirements of various specific applications. Also using an ammonia gas diffusion system, by changing the type of the magnesium salt reactant and the type of the additive, a magnesium hydroxide product different from the spherical morphology can be obtained, that is, flaky magnesium hydroxide with good dispersibility.