Preparation And Application Of Flame Retardant Type Nano-powders Of Mg(oh)₂ And Ldhs Using The New Reactor

Nano-materials show many unique natures due to the quantum size effect, small size effect, surface effect and macroscopic quantum tunneling effect, which make the application involve in catalysis, barrier, fire retardant, filter, light absorption, medicine, new materials, magnetic media, and so on. However, the fantastic activity let the nanoparticle apt to agglomerate, which cannot bring the nano-effect into full play. Except that a lot of nano-materials just stayed at the laboratory stage with a small amount of synthesis, thereby limited their applications of industry and daily life. In addition, Flame retardant used in the current market is still dominated by halogen elements, which bring greater hidden trouble to environmental safety and environmental protection. In this paper, the main purpose is basing on the above existing problems to design and prepare two new reactors to explore large scale synthesis of inorganic nanopowders. The nanoparticles were applied as fillers by the maens of in situ polymerization and filling process to prepare polymer nanocomposites, meanwhile, the related performances were also examineed, which are as follows:During the process of manufacturing the reactor with composite shear strength to prepare needle-like OA-MH, mechanical force, fluid force and gas force consist of composite shear strength generated by reactor with special construction; sodium oleate as modifier; all of which control the crystal nucleation and growth, and the role of secondary flow in the shear stress was first employed to prepare inorganic nanomaterials. Mechanical force, fluid force and gas force not only prevent nanoparticles from agglomerating, but also cut large particles into smaller ones, so that the particle size tends to be homogeneous. Special multi-chamber structure and the reaction chamber between the baffle and the baffle hole structure along with high-speed stirring mixer makes the fluid perform circulation mode of spread-up flow-converge, which not only extend the effective path of fluid in the reaction chamber to limit the speed of fluid flow, but also makes shearing, reacting and surface modifying are all sufficient by the action of mechanochemistry and fluid force chemistry. Gas charging along with introducing a certain amount of surfactants or similar surfactant, not only prevents particles from agglomeration, but also forms a thinner and more stable film when the system under the action of composite shear strength, in addtion, coupled with the low temperature, the particles grow mainly in one dimension, and thus the needle like product was gained.In the process of manufacturing the two-stage reactor to prepare LDHs nanosheets, the surface renewal model and eddy cell model was firstly employed to the preparation of inorganic nanomaterials on the basis of LaMer model. In the process of preparation of nanoparticles, impeller mixer and scattering groove mainly achieve the level of meso-scale distribution and make reactants rapidly and uniformly micro-mix, crystal nucleation was mainly occurred in this stage. The agitator make mass transfer achieve a level of molecular scale, in this way, the growth of nuclei is simultaneous, and crystal growth performs mainly in this stage; impeller mixer, scattering groove and agitator vertically arrange in the way of top-down in space and linked by drive bar, which breakthrough the drawbacks of the traditional reactor with only function of dispersing or mixing, or of the crystal nucleation and growth cannot separate. Gas injected from the bottom of the reactor to form a large number of macro and micro gas eddy in the liquid outside and inside separately, which further promote the quality of mass transfer, thus the particle with smaller size and narrower distribution was obtained.In the process of in situ bulk polymerization to prepare LDHs/PMMA nanocomposites, combination of ultrasound and mechanical stirring is an effective method to promote ZnMgAl-CO₃ LDHs colloidal particles homogeneously dispersed in ethanol. After modification of outside surface by oleic acid molecules, LDHs can uniformly dispersed in MMA monomer, thus the nanocomposite where the nanoparticles well dispersed can be prepared by the process of radical polymerization. The addition of ZnMgAl-CO₃ LDHs nanoparticle is only 2wt%, the thermal stability of OA-ZnMgAl-CO₃ LDHs/PMMA nanocomposite is obviously higher the one of ZnMgAl-CO₃ LDHs/PMMA nanocomposite and PMMA, which was attribute to good dispersion of modified nanoparticles and the strong adhesive force with the polymer matrix.The process of filler in filled EVA, the standard spline was prepared by using twin-screw extruder and injection molding machine, and relative properties were examined. When the MH content is 4wt%, the viscosity occured a mutation, even lower than the one of MH content is 2wt%, which indicated that the content of 4wt% MH is optimum one for fluidity and tensile strength; meanwhile, it also shows that better processing properties of polymer composites can improve the mechanical properties of polymer. The additive amount of ZnMgAl-CO₃ LDHs/MH (mass ratio1:1) within the amount of 16wt%—20wt%, the combustion performance achieve UL-94 (1.5mm) V-2 level, which due to ZnMgAl-CO₃ LDHs nano-particles play the role of catalytic charring, and two kinds of particles act as each other's thinner thinner, so that groups of particles is not easy to agglomerate, which fully show synergistic properties of nanoparticles.