以水菱镁矿为原料,通过“煅烧-水化-煅烧-水热”的简单合成路线制备了高分散六角片状的阻燃型纳米氢氧化镁。确定初步工艺后,探究了氧化镁用量、水热温度和水热时间对氢氧化镁结晶度和形貌的影响,确定最佳工艺水热条件：氧化镁用量为10%~25%（质量分数）、水热温度为150 ℃、水热时间为3 h。在水热过程中,分别向反应体系中加入聚乙烯吡咯烷酮（PVP）、十六烷基三甲基溴化铵（CTAB）、聚乙二醇6000（PEG6000）和聚乙二醇200（PEG200）,考察了不同改性剂及改性剂用量对氢氧化镁颗粒结晶度和分散性的影响。结果表明在4%（质量分数）PVP的条件下,能很好地改善纳米氢氧化镁的分散性,并得到了分散性好、晶形完整、粒径均匀、直径为300~400 nm、厚度为40~60 nm的六角片状纳米氢氧化镁。

Nano-sized highly-dispersed hexagonal magnesium hydroxide as the flame retardant was prepared from hydromag-nesite by a simple synthesis route by calcination-hydration-calcination-hydrothermal method.After the initial process was con-firmed,the effects of magnesium oxide（MgO） dosage,hydrothermal temperature and hydrothermal time on the crystallinity and morphology of Mg（OH）₂ were investigated.Finally,the optimized hydrothermal conditions were determined as follows：MgO dosage was 10%~25%（mass fraction）,hydrothermal temperature was 150 ℃ and hydrothermal time was 3 h.Polyvin-ylpyrrolidone（PVP）,cetyltrimethylammonium bromide（CTAB）,polyethylene glycol 6000（PEG6000） and polyethylene gly-col 200（PEG200） were separately added to the reaction system during the hydrothermal process to explore the effects of dif-ferent modifiers and mass fractions of the modifier on the crystallinity and dispersibility of Mg（OH）₂ nanoparticles.Result showed that the dispersibility of Mg（OH）₂ nanoparticles can be well improved using 4%（mass fraction） PVP and finally hexa-gonal nano-Mg（OH）₂ with high dispersibility,complete crystal shape,uniform particle size,300~400 nm diameter and 40~60 nm thickness was obtained.