六角片状氢氧化镁(001)晶面优先生长条件的研究

Study on the Priority Growth of(001) Plane of Hexagonal Magnesium Hydroxide

以常温工业合成氢氧化镁为原料,采用水热法制备六角片状氢氧化镁阻燃剂。研究了水热条件对氢氧化镁(001)晶面生长的影响并从生长基元的角度对其进行了解释。采用SEM、XRD、激光粒度仪和接触角测试仪对水热处理后的氢氧化镁进行表征。结果表明,原料初始粒度越小越有利于(001)晶面生长,当水热介质中碱浓度为6～8mol/L、水热温度为140～180℃时,氢氧化镁(001)晶面的生长速度最快,当氢氧化镁的含量大于15wt%时会明显抑制(001)晶面的生长。

The flame retardant hexagonal magnesium hydroxide was prepared by the hydrothermal treatment method using the normal magnesium hydroxide as raw material. The influence of different hydrothermal conditions on the growth of（001） plane was investigated. The hydrothermally treated products were characterized by SEM,XRD,laser particle analyzer and contact angle analyzer. The experimental results indicate that the minor initial particle size of raw material is beneficial to the growth of crystal plane（001）. In hydrothermal system,the growth rate of（001） plane of magnesium hydroxide is faster between 6-8 mol /L of sodium hydroxide than that at other concentrations. As the hydrothermal temperature increasing,the growth of the（001） plane becomes more integrated,especially between 140℃ to 180 ℃.（001） plane growth is significantly inhibited when the solid content of magnesium hydroxide exceeded 15wt%. Finally,the phenomenon was explained by the polyhedron growth unit theory mode.