The Preparation And Dispersion Of The Magnesium Hydroxide Nanowhiskers

The new functional material, magnesium hydroxide (MH) nanowhiskers, is a kindof environmental protection material with flame retardancy and reinforcing properties.At present, the study of MH nanowhiskers is still at the experimental stage and thestudy of whiskers’ dispersion is relatively rare. In this paper, the research had beentaken systematically for the preparation and dispersion of MH nanowhiskers. And basedon the experiment the ideal results had been obtained.In this thesis, MH nanowhiskers were prepared by the magnesium oxysulfatewhiskers (MOS), of which raw material being magnesite, and NaOH via the method ofhydrothermal conversion. To investigate the property of synthetic product, the factor ofMOS property and its concentration, mole ratios of NaOH/MOS, additive and itsaddition, reaction temperature, reaction time and agitation intensity were studied by themethod of single-factor. The SEM, XRD, EDS, FT-IR and TG-DSC were used toanalyze the surface morphology, phase composition, elemental composition, functionalgroups and thermal stability of the synthetic product. According to the statistics methodof single whisker’s percentage in a certain amount of total content (≥200), thedispersion of MH nanowhiskers was characterized.The optimal preparation technology of the MH nanowhiskers was gained throughcontinuous adjusting and optimizating the influence factors. The optimal preparationparameters are that, the mole concentration of MOS which has diameter less than200nm and L/D more than100for0.03mol/kg, the mole ratio of NaOH to MOS for4.5:1, the additive for sodium stearate, the ratio of sodium stearate to MOS for2%, thereaction temperature for180℃, the reaction time for4h, the stirring speed for100r/min.The product which is prepared at the optimal conditions has the average morphology foraverage diameter (D) of85nm, average length (L) of14μm and average ratio of L/Dfor100. The diameter, length and L/D distribution of whiskers are narrow. And each ofthem in the range of80~95nm,10~15μm and100~180are57%,66%and70%of thetotal content (≥100) respectively. The XRD pattern showed that the synthetic product ispure MH. Because the whiskers’ surface adsorbed carboxyl-carbon chain, its dispersion is improved obviously for the single whisker’s percentage of80%. The decompositiontemperature range of the MH nanowhiskers is318~490℃, the productgets the fastestthermal decomposition rate when the range is380~420℃. The research results havecertain reference value for improving the dispersion and preparation of whiskers.