Magnesium hydroxide is a green flame retardant with many researches and rapid development. It has many advantages, such as no secondary pollution, good thermal stability, no volatilization, no precipitation, no toxic gas, no corrosion processing equipment, smoke abatement effect is remarkable, substrate carbonization effect is efficient, rich in magnesium resources. However, prepared by traditional methodsMagnesium hydroxideIt has strong polarity and hydrophilicity. The particles tend to have secondary coagulation, poor dispersibility and poor compatibility with non-polar polymer materials, and it is difficult to form a good combination and adhesion at the interface. Therefore, as the content of magnesium hydroxide in the polymer material increases, its processability and mechanical properties also decrease sharply, limiting its application. In order to make magnesium hydroxide better used for flame retardancy of polymer materials, there are mainly the following methods:

(1) ultrafine particle size. at the processing temperature of the polymer material,Magnesium hydroxidePresent in the system as particles. Generally speaking, when the filling amount is the same, the finer the particles of magnesium hydroxide, the more uniform the dispersion, the more obvious the flame retardant effect, the smaller the negative impact on the physical and mechanical properties of the material, and even the plasticization of rigid particles.

(2) ChangeMagnesium hydroxideThe crystal structure is prepared in a special shape (hexagonal). Mixing magnesium hydroxide at room temperature is usually used for hydrothermal modification. In a specific high-temperature and high-pressure aqueous solution, magnesium hydroxide undergoes crystallization reorganization through dissolution and recrystallization growth process, changing the structure and shape of the crystal. Hexagonal magnesium hydroxide has a unique advantage as a flame retardant because of its low surface polarity and surface, good solubility when mixed with polymer materials. In addition, the hexagonal magnesium hydroxide is easy to be mixed with the resin, but also has a reinforcing property, so that the mixing processability is good.

(3) Surface modification treatment of magnesium hydroxide. Magnesium hydroxide is a kind of polar inorganic compounds, hydrophilic. Even with very dry magnesium hydroxide, there is not negligible water in the crystals. Therefore, magnesium hydroxide is easy to agglomerate when mixed with polymer materials, and has poor compatibility with polymer materials, which makes the surface of the matrix defective, rough and dull. After the modification of magnesium hydroxide, the grain eliminates the surface polarity, improves the dispersion, compatibility and affinity of the polymer material, has better flame retardant performance, plays the role of reinforcing agent, and improves the mechanical strength of the polymer material.

The above is what I want to talk about today. I believe you already understand. Of course, in addition to the above three points, you can also choose other flame retardants andMagnesium hydroxideComposite, in order to improve the flame retardant efficiency, effectively improve the flame retardant performance. In the flame retardant technology, the synergistic effect can not only produce a more effective flame retardant system, but also reduce the use of chemical reagents in other flame retardants and improve the flame retardant efficiency.