硅藻土基表面有机化氢氧化镁的制备及性能

针对现有氢氧化镁阻燃剂在制备过程中存在氢氧化镁浆料过滤性能差的问题，采用正向沉淀法，以六水氯化镁和氢氧化钠为原料，在制备氢氧化镁的过程中加入硅藻土和油酸，制备出了硅藻土基表面有机化氢氧化镁。通过过滤性能测试考察了硅藻土添加量对氢氧化镁浆料过滤性能的影响，同时采用全自动比表面及孔径分析仪（BET）、场发射扫描电子显微镜（FESEM）、傅里叶红外光谱仪（FTIR）、同步热分析仪（STA）等对产物进行了分析。过滤性能和BET分析表明，添加硅藻土后，氢氧化镁浆料的过滤速率明显提高，当硅藻土与氢氧化镁质量比为0.10∶1时，所制备的硅藻土基表面有机化氢氧化镁的孔容最大，且氢氧化镁浆料的过滤性能提高了61.9%；FESEM分析表明，硅藻土的表面负载了分散性较好的片状氢氧化镁；FTIR分析表明，油酸成功地结合在氢氧化镁和硅藻土表面，提高了硅藻土基氢氧化镁的疏水性；热重（TG）分析表明，硅藻土对氢氧化镁具有协同阻燃效应，少量硅藻土的加入可以提高氢氧化镁的热稳定性，提高残重率，降低热释放速率，延长热分解时间。

Preparation and property of diatomite supported hydrophobic magnesium hydroxide

In order to solve the problems of filtration difficulty of the magnesium hydroxide slurry in the preparation of magnesium hydroxide flame retardant,diatomite supported hydrophobic magnesium hydroxide was prepared by positive precipitation method with MgCl₂·6H₂O and NaOH as raw material and adding diatomite and oleic acid as a surface modifier in the preparation process. The influence of diatomite amount on the filtration property of magnesium hydroxide slurry was discussed by means of filtration property test. Simultaneously, the products were characterized by Automatic specific surface and aperture analyzer (BET), Field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR) and Thermogravimetry-differential scanningcalorimetry (STA). The results of filtration property test and BET showed that the filtration rate of magnesium hydroxide slurry was increased evidently after adding diatomite. When the mass ratio of diatomite to magnesium hydroxide was 0.10∶1, the pore volume of diatomite supported hydrophobic magnesium hydroxide was the biggest, and the filtration rate of magnesium hydroxide slurry was increased 61.9%. The result of FESEM indicated that the surface of diatomite was loaded with flake magnesium hydroxide with good dispersion. The result of FTIR showed that OA bonded to the surface of magnesium hydroxide and diatomite with excellent hydrophobic properties. The result of TG found that diatomite had a synergistic flame retardant effect on magnesium hydroxide. Adding a small amount of diatomite can improve the thermal stability of magnesium hydroxide, increase the residual weight ratio, reduce the heat release rate and increase the thermal decomposition time.