Study Of Surface Modification And Properties Of Magnesium Hydroxide

Metal hydroxides as smoking and toxic-free additives have been extensively used in hatogen-free flame-retardant polymeric materials. However, their fatal disadvanta- ges are low flame -retardant efficiency and thus very 1arge usage amount is needed to meet the flame retardant requirement, which lead the mechanical and processing p- roperties of materials to drop down sharply. So, the surface of magnesium hydroxide should be modified in order to improve intermisibility and mechanical processing properties of materials.(1) The surface of magnesium hydroxide is modified with stearic acide and sodium stearate , and this paper analyzes the influence of factors such as quantities of stearic acide and sodium stearate, time, temperature. The influence of the different reaction conditions on the modified magnesium hydroxide samples were investigated by the single factor condition experiment. The dispersity of the polymer blend formed by the modified MH , nonmodified MH and PVC with the proportion of 4:6 and 7:3 respectively had been studied. The experimental result shows that the dosage of modifier is 8% and the modified time is 40 minutes and the modified temperature is 70℃, and using sodium stearate is better than stearic acide in the same condition. Using SEM and CHEMICAL MAPPING indicated that the dispersity of using sodium stearate modified MH in PVC is good.(2) Magnesium hydroxide is prepaired by one step using oleic acid, oleic acid / polyethylene glycol 600 as a surface modification agent. The same method was used by stearate and stearate / polyethylene glycol 600 as a surface modification agent. The experiment result is the particle size adding polyethylene glycol 600 were smaller ; Stearate was better for the modification of sodium stearate , and have good dispersion in PVC.(3) Exfoliated MH / PS nanocomposites were obtained by soap-free emulsion polymerization method without the aid of any surfactant. The MH/PS nanocomposite was analyzed by IR, TGA . The result is MH / PS nanocomposite has good thermal stability.(4) The products which were modified sodium stearate were added into polyethylene , the ratio were 10,20,30,40 percent. The effect of the mount of four flame retardant on the mechanical and flame retardant properties of the composites were discussed. The experimental results is the dosage of 20% is the best giving attention to two or more things on the mechanical and flame retardant properties.