Preparation of modified magnesium hydroxide and its application in PA66

There are the advantages of flame retardant, filling, smoke suppression, non-corrosion processing equipment for environmental flame retardant magnesium hydroxide, so it is widely used in engineering plastics, rubber and other materials. The dispersibility and compatibility of magnesium hydroxide in polymer materials are poor. Therefore, it is necessary to modify the surface of magnesium hydroxide. Taking MgCl2 and NaOH as raw material and fatty alcohol polyoxyethylene ether-9(AEO-9)/ Sodium Dodecyl Sulfate (SDS) as composite modifier, modified magnesium hydroxide was prepared by direct precipitation method. The modification results were characterized by oil absorption value, activation index, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and other methods. When modification time is three hours and modifier dosage is 4.0g/mL, the modification effect of Mg(OH)₂ prepared by the AEO-9/SDS treatment process is the best. It was shown that the composite modifier only acted on the surface of Magnesium Hydroxide (MH) powder and did not change its crystal structure, and its surface was changed from hydrophilic to hydrophobic, and the dispersibility and thermal stability were significantly improved compared with unmodified magnesium hydroxide. The Mg(OH)₂ before and after the modification were applied to Polyamide 66 (PA66) to test its flame retardant and mechanical properties. The results show the modified Mg(OH)₂ has good compatibility with PA66.