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Properties of Magnesium hydroxide flame retardants

Under normal temperature conditions, the synthetic magnesium hydroxide is mostly irregular sheet-shaped crystal or non-fixed crystals. The size of the grains in the <101> orientation through X-ray diffraction is lower than 7 × 10-8;Small; the particle size distribution range is wide, between 0.5-8 μm; larger than the surface area, usually at 20-100m2/g; the grains have a strong condensing into a dumplings, which is easy to reunite to form two two with a particle size of 10-100 μm.The secondary particle size and the interface of the polymerization material form a gap, which hinders the dispersion of magnesium hydroxide in the polymer material.

Secondly, with the help of X-lit diffraction, it can be found that ordinary magnesium hydroxide crystals in the <101> illegal internal stress should be between 3 × 10-3-10-2. Strong, with positive charge and hydrophilicity. In this way, even after the magnesium hydroxide is dry, there is still water in the crystal that cannot be ignored, which is difficult to compatible with polymer materials, which has a serious impact on the mechanical strength of the material. Therefore, the flame retardant effect of polymer aggregation materials is not ideal, and it will greatly reduce the mechanical properties and strength of the material.

In order to make the flame -retardant magnesium hydroxide, ordinary magnesium hydroxide must be modified. Generally speaking, the magnesium hydroxide of the non -fixed structure uses the surface active agent to modify it to eliminate the polarity of the surface and compare it in organic materials. However, due to the larger surface area of ​​magnesium hydroxide hydroxide, the amount of addition in organic polymers should be at least more than 60%in order to get a certain flame retardant effect. At the same time, excessive additives may reduce the mechanical performance and physical properties of polymer materials, especially the changes in mechanical strength such as bending strength and tension strength. In order to improve the flame retardant performance of magnesium hydroxide, the amount of magnesium hydroxide in organic polymer materials should be reduced.

In addition, the modified treatment of ordinary magnesium hydroxide, the crystal structure rules, uniform particle size, and smaller than the surface area of ​​the obtained magnesium hydroxide, basically eliminating the surface polarity. On the one hand, the compatibility and decentralization of magnesium hydroxide can be improved in organic polymer materials, and then play a better flame retardant effect. On the other hand, it can also act as a reinforcement agent to improve the mechanical strength of organic materials.