Study On Preparation And Surface Modification Of Flame Retardant Magnesium Hydroxide In Pilot Palnt

Inorganic flame retardant magnesium hydroxide (MH) compound has been widely used in polymeric materials for its smoking- and toxic-free merits. In this paper, the preparation of magnesium hydroxide in pilot trial using magnesium chloride and ammonia solution as raw materials was studied. The effects of temperature and titration process were contrasted respectively both in lab trial and pilot trial. Besides, the surface modification of magnesium hydroxide with silane coupling agent were also investigated. By means of SEM and XRD, the difference of magnesium hydroxide prepared in lab trial and pilot trial was compared. The performances of surface modification were evaluated by FT-IR and TG.(1) Compared to the products prepared in lab trial, magnesiumhydroxide are smaller sized, lower ratio of I₀₀₁/I₁₀₁ and agglomerated more seriously in pilot trial. All above negative influences can be eliminated through lengthening feeding time of raw materials and doubled the feed solution's concentration simultaneous, then the larger sized and well-dispersed magnesium hydroxide are successfully prepared.(2) The effects of temperature and titration process in pilot trial onthe preparation of MH shows that, when using ordinal- titration process, the particle size and dispersion of magnesium hydroxide are both increasing with the increase of temperature. However, when using reverse-titration process, magnesium hydroxide is with smaller particle size, lower thicknessand better crystallization. The results acquired in pilot trial are consistent with lab trial.(3) The modification effects with vacuum distillation method, wetmethod, one-step method and situ-modification method are compared. One-step method is the best modification process for its simplest process and less filtration time. Compared with unmodified magnesium hydroxide, the product with one-step modification process exhibits excellent hydrophobic property and dispersion ability. The flame retardation and mechanical property are also improved greatly in the polymeric materials.