Preparation And Performance Characterization Of The Nanometer White Carbon Black

Hydrated silicon dioxide with the name of white carbon black has thecharacteristics of high purification, low density, large specific surface area, finedecentralization, good optical and mechanical performances. So it has been widely usedin many fields, such as rubber, plastics, medicines, paints, household chemicals,activaor carriers, compound materials of macromolecule, electronic encapsulationmaterials and precise ceramic materials．White carbon black nanoparticles not only have excellent properties, but alsohave the feature of nanoparticles. It is one of the prospective inorganic functionalmaterial. But its application has been limited for the serious aggregation during thepreparation. In this thesis, with the rule of solubility white carbon black nanoparticleswere prepared taking wollastonite as raw material and sulfate as the precipitant, and thenanoparticles’ surface energy were decreased by the addition of surfactants. Throughcontinuous optimization of preparation parameters, the optimal preparation conditionswere obtained by the single-factor method studied on the concentration of reactant,hydrothermal temperature, pH, agitation intensity, dropping speed of H2SO4,consumption and kind of additive. Its particle size distribution was tested by laserscatter analysis. The SEM, and FT-IR were used to analyze the surface morphology andfunctional groups of white barbon black surface, respectively. The phase analysis andthermal stability of the product were detected by XRD and TG-DSC. The by-product,calcium sulphate, was also obtained during the experiment preparation. During theresearch, the calcium sulphate whiskers and wastewater had been recycled.The white carbon black nanoparticles were prepared by the method of precipitationmethod with taking wollastonite as raw material. The optimal preparation conditions ofnanometre white carbon black were that, the stirring speed for700~900r/min, thereaction temperature for85℃, the reaction time for30min, dropping speed of H2SO4for0.01mol/min, initial H2SO4for0.34mol/kg, the reactant concentration for3.9%~4.0%, mole ratio of H2SO4/CaSiO3for2.0:1, pH for8, the content of sodium dodecyl benzenesulfonate for2.0%.The product prepared at the optimal conditions had good dispersivity with averagediameter less than100nm, XRD examination showed that the molecular formula wasSiO2·0.5H2O.FT-IR test indicated that agglomeration behavior had been decreased afterthe addition of sodium dodecyl benzene sulfonate for the reducing of surface energy anddissociating hydroxyl groups. FT-IR results showed that agglomeration behavior wasdecreased after the addition of polyacrylamide for the reduction of surface energy anddissociating hydroxyl groups. TG-DSC curves showed that the product had threeendothermic peaks at85℃~115℃、115℃~500℃and500~900℃. They were watersplitting on surface adsorption, dehydratio in the adjacent-OH, decomposed by carbonin the organics respectively. The TG showed that the crysta instruction of the productwas still SiO2, and the result of TG indicated that the white carbon black nanoparticleshad good thermal stability.The achievement had a certain guiding significance for development ofhigh-quality wollastonite and nano-white carbon black.