Advanced Materials Research Vols. 1004-1005

Abstract: Perovskite Ba_0.7Sr_0.3TiO₃ nanocubes with a hollow structure were prepared by molten hydrated salt method at 180 °C for 15 h, using Ba (OH)₂·8H₂O, Sr (OH)₂·8H₂O and anatase-TiO₂ as raw materials without any additive or template. The phase composition, morphology and microstructure of the products were characterized by XRD, SEM, TEM and HRTEM. The XRD result indicates that the products are phase pure cubic Ba_0.7Sr_0.3TiO₃, with the calculated unit cell a=0.3965 nm. The SEM, TEM and HRTEM results show that the products with polycrystalline structure are composed of the hollow nanocubes whose average edge length is about 180 nm, and their morphologies are greatly influenced by reaction temperature and reaction time. In addition, the formation mechanism of the hollow nanocubes also was discussed.

Abstract: In order to prepare high reflectivity titanium dioxide, by sol - gel method after nano-titanium dioxide powder, which silane coupling agent KH-570 covering it and make its surface modification.When the reaction temperature is 40 °C, drop accelerated rate 1.5mL/min, calcination temperature about 600 °C, got titanium dioxide with relatively high reflectivity and particle size in around 65 nm.When the amount of the silane coupling agent is 0.5%, the pH of reaction system is 6.5, and the reaction time was 1.5h, the nano-modified titanium dioxide particles with high reflectance.

Abstract: Nanoparticles and their ordered arrays have many important applications in fields such as electronic, optical, memory storage devices and sensors. Herein, a simple method was used for fabricating three-dimensional ordered gold nanoparticle arrays with template technique. Gold films were deposited onto anodic aluminum oxide by using electron beam evaporation. After thermal annealing, interestingly, order arrays of gold nanoparticles were obtained by a thermodynamically driven self-assembled process. The spectrum taken by UV-Vis spectrophotometer demonstrates clear surface plasmon resonance at around 500 nm, which appears blue-shift compared with usual gold nanoparticles.

Abstract: One dimensional nanomaterials are used as the basic and significant parts to fabricate nanodevices. Silver nanowire is a promising conductive particle, which can be used in conductive adhensives. The research is about the effects of the control agents, reaction temperature, and reaction time on the morphology and size of the product. And figure out an effective way to control the nucleation and the morphology of silver nanowires.

Abstract: Size controllable Barium titanate nanoparticles were synthesized in microemulsion consisting of water, OP-10, hexanol and cyclohexane under atmospheric pressure and low temperature, with Ba (OH)₂·8H₂O and tetrabutyl titanate used as starting reactants. Products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The results show that 65°C is the proper temperature for the synthesis. The particle size can be controlled by varying the reactants’ concentration, ω value (molar ratios of water to surfactant) and aging time.

Abstract: Titanium carbonitride (TiCN) nanocrystaline powders were syntheiszed by reactive ball milling of titanium, graphite and urea. GN-2 ball milling was used and the rotation speed was 600rpm. The ratio of ball to material was 30:1, the milling time was from 10 hours to 50 hours. The powders milled for different time were analyzed by X-ray diffraction. The results show that TiCN powders can be synthesized by milling 10 hours, although some raw materials remained. After milled for 50 hours, the raw materials can reactive completely to form TiCN and the grain size of the TiCN powder was about 7 nm.

Abstract: The transparent glass-ceramics containing nanocrystalline AlNbO₄ phase in the 25Al₂O₃-27Nb₂O₅-40SiO₂-7Na₂O-2Eu₂O₃(wt%) glass were prepared by the melt-quench technique followed by a two-stage controlled heat treatment. Crystalline phase were indentified using X-ray diffraction (XRD) which AlNbO₄ phase was found. Scanning electron microscopy (SEM) was used to image the crystalline phase morphologies. The luminescence spectra of Eu³⁺-doped glass and glass-ceramics were recorded at 393 nm exciation wavelength and the luminescence intensity is found to be increase with heat-treatment time due to increase in crystallinity. The high intensity ratio of ⁵D₀-⁷F₂ to ⁵D₀-⁷F₁ indicates that the Eu³⁺-doped nanocrystalline AlNbO₄ glass-ceramics are promising candidate materials as red-light source.

Abstract: This work reports the flammability properties of Nanocomposites reinforced with silica and PTFE nanoparticles and toughened with an elastomeric ethylene-vinyl acetate (EVA). Through trial and simulation study of the flame retardant thermoplastic polymer and melting characteristics of PP in the combustion process.The study found that modified PP composites have good flame retardancy compared to PP in case of fire relatively.In the study,the melting characteristics of the thermoplastic polymer affected the mass loss rate in the combustion stage.Nanocomposites experienced low plastic mass loss compared with PP, this has been related to pyrolysis mechanism of polymer.In general,The polymers undergoing depolymerization will lead to a rapid volatilization and therefore experienced much less melting.The results showed that:total heat release of nanocomposites was higher than polypropylene, while the average heat release rate, the maximum heat release rate, the average effective heat of combustion, the average mass loss rate, the average specific extinction area, and other indicators were lower than polypropylene.

Abstract: Ti-PILCs (Ti-pillared Montmorillonite Nanocomposites) was obtained from which Ti (n-C₄H₉O)₄ cross-linked Na-montmorillonite through Sol-gel means. The analysis results of BET, FT-IR and TG-DSC shows that a large amount of middle porous of 2-4nm exist in the Ti-PILCs interlayer and the porous distributing is not uniformity, meanwhile, the thermal stability is over 900 °C. It has good application prospect to use as carrier materials material of oil catalytic and cracking.

Abstract: In isopropanol-water mixture, a polymer emulsion was prepared through the radical copolymerization [1,2] of styrene, acrylonitrile and 4-vinyl pyridine in the presence of azodiisobutyronitrile (AIBN) and a reactive emulsifier which was synthesized through the addition reaction of 2-isocyanatoethyl methacrylate and methoxypolyethylene glycols (Mn ≈ 2000). The polymer particles were narrowly distributed and had an average size of about 110 nm in diameter. Hydroxypropyl cellulose was used as the binder resin for the emulsion film. The emulsion coating was prepared by coating the mixture of the polymer emulsion and the water solution of the binder resin on aluminum substrate and dried at about 80°C. The resulted film can be easily removed from the substrate with water rinsing. However, once the coating is heated at a temperature which is much higher than the glass transition temperature (Tg) of the particle polymer (e.g., 150°C) for a short period of time, it could no longer be removed from the substrate by water. On the basis of the above work, a water soluble infrared-absorbing dye (IR dye) was incorporated into the emulsion coating and exposed to computer-controlled IR laser (830nm) scanning. The exposed areas could not be removed with water cleaning, whereas the non-exposed areas could still be easily removed with water. Negative images were obtained. Hence, the emulsion coating can be used in developing chemical-free CTP plates required by green printing industry.