The Preparation Of Flame Retardant Grade Magnesium Hydroxide With Lime Milk

With the wide application of high polymer material,its flammability also caused the attention of people.So it is important for polymer materials to choose suitable flame retardant which does not affect its processing performance.What’s more,magnesium hydroxide is called environmentally friendly flame retardant because of its non-corrosive,non-toxic and tasteless characteristics,Thus it is the primary choice of organic polymer flame retardant.In this paper,the purpose is getting the magnesium hydroxide flame retardant with natural brine and lime milk as raw material.There are three steps:synthesis in room temperature,hydrothermal method and the surface modification.The main factors that effects on the structure and the surface modification of magnesium hydroxide are investigated.And the product under the optimal conditions are analysed and characterized by SEM,XRD,IR,BET and so on.The process of synthesis in room temperature is to use brine and lime milk to get larger particles magnesium hydroxide,and the main factors are investigated.The optimum conditions for synthesis of the magnesium hydroxide in room temperature are as follows:temperature 90℃,16 mol/LCaCl₂,0.1111 ml/min MgCl₂.At this time,the characterization results showed that the specific surface area of the products was 8 m²/g and the morphology was flake,but particle size was not uniform and still a strong phenomenon of agglomeration.Hydrothermal method is to make magnesium hydroxide neat,and the main factors are investigated.The optimum conditions for hydrothermal synthesis of magnesium hydroxide are as follows:2 mol/L sodium hydroxide was mineralizer,Solid content was150 g/L,temperature was 160℃,the reaction time was 4 h.At this time,the characterization results showed that the specific surface area of the products was 5 m²/g and the morphology was hexaganol shape.Besides,particle size was uniform and has excellent dispersion.The surface modification process is to use the appropriate modifier coating of magnesium hydroxide,in order to get hydrophobic and oleophilic products.First of all,it is extracted of modifying agent from two kinds of samples abroad.Then,the main factors are investigated.The last,the modified product samples contrast with Japanese in all aspects.The optimum conditions for the surface modification of magnesium hydroxide are as follows:wet modified with mixing of 7000 r/min,modifier A was modifier,adding amount was powder mass fraction of 3%.At this time,the characterization results showed that the modified product was hydrophobic and oleophilic.In the end,the product under the optimal conditions are analysed and characterized by SEM,XRD,IR,TG-DSC.The modified product are very similar with the Japanese sample in all aspects.So the modification process is perfect.The application of the modified magnesium hydroxide needs to do in-depth experiments and research.