Magnesium hydroxide is an inorganic flame retardant filler for polymer matrix composites with good application prospect. Like aluminum hydroxide, magnesium hydroxide flame retardant plays a flame retardant role by chemical decomposition, endothermic and water release when heated, so it has the advantages of non-toxicity, low smoke and stable chemical properties of magnesium oxide formed after decomposition, and no secondary pollution. However, compared with halogen-containing organic flame retardants, the filling amount is generally more than 50% in order to achieve considerable flame retardant effect. Because magnesium hydroxide is inorganic, the compatibility between the surface and the polymer base is poor, so the filling amount is so high that if the surface modification is not carried out, it will be filled to the polymer. After the material is in the material, the mechanical properties of the composite will decrease. Therefore, it is necessary to modify the surface of the material in order to improve its compatibility with the polymer base material, so that the mechanical properties of the filling material do not decrease, and even some of the mechanical properties of the material are improved.
Magnesium hydroxide as a flame retardant has the following advantages
1. It can play the role of flame retardant and filling.
2。 Because of the high processing temperature of magnesium hydroxide, it can be used in resin with high processing temperature.
3. It is non-toxic and tasteless, does not generate toxic gas and corrosive gas in combustion, and does not corrode the mold.
4. Not volatile and not affected by water.
5. The high thermal decomposition temperature of magnesium hydroxide is beneficial to increase the processing temperature of plastics, accelerate the extrusion speed and shorten the molding time.
6. Magnesium hydroxide and acid neutralization ability, can neutralize the combustion process of plastic acid gas sulfur dioxide, carbon dioxide and so on.
7. It is favorable for absorbing the combustion heat and improving the flame-retardant efficiency.
8. Magnesium hydroxide has strong smoke suppression ability, low hardness and small friction to equipment.
1. Magnesium oxide produced by combustion and dehydration of magnesium hydroxide is a kind of high strength and high heat resistant material, which can be used as a protective wall to isolate fire source and toxic and harmful gases. Magnesium hydroxide and acid have strong neutralization ability, and can neutralize acid gas SO2,NOx,CO2 produced by plastic combustion quickly.
2. The particle size distribution is uniform, and the compatibility with the substrate is good, which has little effect on the mechanical properties of the product.
3. The decomposition ability of magnesium hydroxide is high, the flame retardant efficiency is high, the smoke suppression ability is strong, the hardness is small, and the friction to the equipment is small, which is helpful to prolong the life of the equipment.
4. The thermal decomposition temperature of magnesium hydroxide is 340 ℃, which is 100 ℃ higher than that of aluminum hydroxide, which is beneficial to the improvement of plastic processing temperature, the acceleration of extrusion speed, the improvement of molding effect, the shortening of molding time, the high surface gloss of the product, and no surface defects. At the same time, it ensures the super peeling strength.
And 5, the price is low, the magnesium hydroxide is half the price of the aluminum hydroxide, the filling amount is large, and the cost of the product can be greatly reduced.