Advanced Materials Research Vols. 881-883

Abstract: nano-SiO₂ modified core-shell polyacrylate composite emulsion was synthesized by seeded semi-continuous starved pre-emulsion polymerization and sol-gel technique. The influence of 3-methacryloxypropyltrimethoxysilane(KH-570), tetraethoxysilane(TEOS) on the properties of emulsion and film were studied. The SiO₂/silicone polyacrylate composite latex and the resultant films were characterized by fourier transform infrared spectroscopy(FT-IR), differential scanning calorimeter(DSC), thermogravimetric analysis(TGA), water contact angle goniometer (WCAG). The results showed that organic silicon and nano-SiO₂ were effectively grafted to the polyacrylate molecular chain. We can observed there are two glass transition temperatures (Tg) in the DSC curve. The water contact angle (WCA) on the PAE film and SSPAE film separately attained 62.5°and 85.5°.

Abstract: TiO₂ microspheres were prepared in a solvothermal process without involving any templates. Meanwhile, the photocatalytic activity of TiO₂ microspheres was studied using p-nitrophenol as a probe. The results indicate that the anatase TiO₂ microspheres with a diameter of 1-8 μm can be obtained using this simple method. Moreover, the as-prepared TiO₂ microspheres display relatively high visible photocatalytic activity with 35.6% of degradation ratio of p-nitrophenol after 150 min irradiation.

Abstract: HgS nanoparticles with adjustable dispersibility have been synthesized at the water/n-butyl alcohol interface and characterized with Xray diffraction, transmission electron microscopy. Meanwhile, the dispersibility of the asprepared HgS nanoparticles in water and nbutyl alcohol were measured, respectively. The results indicate that the cubic HgS nanoparticles could be obtained; and the dispersibility of the HgS nanoparticles can be simply tuned. When Hg (CH₃COO)₂ aqueous solution and nbutyl alcohol solution of thioacetamide are used, the asprepared HgS nanoparticles can be dispersed in water to form a solutionlike suspension. In contrast, when thioacetamide aqueous solution and nbutyl alcohol solution of Hg (CH₃COO)₂ are used, the oil dispersible HgS nanoparticles are obtained. Moreover, the mechanism about the adjustable dispersibility of HgS nanoparticles is discussed.

Abstract: Calcium sulfate is an important inorganic chemical products which is widely used in construction, pharmaceutical and food industries. Especially, calcium sulfate whisker with fibrous structure developed in recent years is further used in rubber, coating, plastic, adhesives, textile, papermaking, and many other industries due to its superior performance and characteristics of environmental protection and nontoxic.The paper reviewed the preparation technology of calcium sulfate according to the different raw materials, especially for industrial waste (by-product).

Abstract: strontium carbonate nanopowder materials were synthesized using Sr(OH)2 and Na2CO3 or CO2 as starting materials in the water by ultrasonic irradiation at 3h,and adding suitable amount of EDTA morphology agent.samples were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD) through separating strontium oxide solution slurry through by centrifuge , washing strontium carbonate slurry by ethanol.XRD and SEM showed that These products were found to be orthorhombic and spherical nanometer strontium carbonate and to be explained the growth mechanism of nano strontium carbonate powder.

Abstract: A series of MO/ SnO₂ (MO=MnO₂, and CoO) core-hell nanocomposites were synthesized by a combined layer-by-layer technique and hydrothermal method. The results showed that SnO₂ or CoO loading enhanced the electron storage ability. When loading 3.0 wt% MnO₂ and 5.0 wt% CoO on SnO₂ nanotubes, after TiO₂ coating electrode was irradiated under UV irradiation for 1 h, the self-discharging time of the MnO₂/SnO₂ and MnO₂/SnO₂ core-hell nanocomposites electrodes was more than 7.5 h and 7.7 h, respectively. In addition, the as-synthesized MO/ SnO₂ core-hell nanocomposites coatings exhibited good photocathodic protection property for metals.

Abstract: In the present study, Fe₃O₄/graphene nanoparticles (Fe₃O₄/GN NPs) were obtained and modified with silane coupling agent. The effects of Cd (II) adsorption experimental parameters such as contact time and initial Cd (II) ion concentration, were investigated. The adsorption dynamics follow the laws of pseudo-second-order kinetics and the rate was controlled by chemical adsorption. The Langmuir isotherm model provided the better correlation between adsorbing capacity and equilibrium concentration.

Abstract: A1₂OC ceramic powder was successfully synthesized via a carbothermal reduction method using Al₂O₃, B₂O₃ and activated carbon powders as raw materials. The effects of synthesis temperature on the phase transformation and micro-morphology of A1₂OC were investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that the content of A1₂OC in the products was increased with the increasing heating temperature. The optimized process for preparing A1₂OC was heating the mixtures at 1700 °C for 2 h in argon flow. A1₂OC particles synthesized at 1700 °C were hexagon plate-like with thickness of 5 μm and size of about 50 μm. Keywords: A1₂OC, synthesis, microstructure

Abstract: The oxidation behaviors and kinetics of in-situ β-Sialon bonded Al₂O₃-C refractories were investigated by TGA techniques via isothermal oxidation experiments at different temperatures. The results show that the oxidation process of in-situ β-Sialon bonded Al₂O₃-C refractories can be divided into three stages: oxidation reaction rate controlling stage, reaction and diffusion controlling stage, and diffusion controlling stage. The oxidation rate controlled by the reaction rate has no obvious changes as the temperature increases. The oxidation rate controlled by the reaction rate and the diffusion rate together has a trend of decline, so is the oxidation rate controlled by the diffusion rate.

Abstract: Andalusite can be used to produce porous refractory with the method of foaming and its properties are very good. The bulk density can be controlled by the quantity of foam easily. The compressive strength can reach almost 9 Mpa (1.0g/cm³). The expansion transmit by pores, the remianing andalusite and the transverse growing of mullite crystal are all good for the stabilization of sample during heating. The agglomeration of foam is bad for foaming slurry while stiring, so one way to well-distribute the pores is enhancing the strength of foams. Andalusite can prolong the lifetime of refractory.