Materials Science Forum Vols. 809-810

Abstract: SnO₂ nanocrystals were synthesized using SnCl₄•5H₂O and NH₃•H₂O as the main raw materials and distilled water as the solvent by microwave hydrothermal. Reaction temperature on the structure and photocatalytic activities of the SnO₂ nanocrystals by microwave hydrothermal process was studied. The phase composition, morphologies and photocatalytic activities of the product were characterized by XRD (X-ray diffraction), SEM (scanning electron microscope), TEM (transmission electron microscope) and photochemical reaction instrument. Results show the crystalline and conglobation of the product have significant effect on its photocatalytic properties. The homogeneous low-agglomerated and well crystallined SnO₂ nanocrystals prepared at 180 °C has good photocatalytic activities during photocatalytic degradation of RhB process.

Abstract: To resolute chiral ofloxacin, we demonstrated a new method of using carboxylated multi-walled carbon nanotubes (MWCNTs) impregnated thin-lay chromatography (TLC). The relative R_F value of carboxylated MWCNTs impregnated TLC was 31.3. A general discussion that focuses on the possibility of functionalized MWCNTs in the field of chromatographic chiral resolution is presented.

Abstract: In this letter, Lawson cypress leaf-like ZnO hierarchical nanostructures with new and interesting morphology were synthesized by electrodeposition in aqueous solution of Zn (NO₃)₂ followed by annealing process, this structure was the first time appearing in ZnO nanostructure. The obtained Lawson cypress leaf-like ZnO hierarchical nanostructures were composed of ZnO nanoparticles with the grain size about 100~200 nm, were observed by scanning electron microscope (SEM), ZnO was detected by X-ray diffraction (XRD), and the highly crystalline structure was demonstrated by high-resolution transmission electron microscopy (HRTEM). Lawson cypress leaf-like ZnO hierarchical nanostructures, which are well-controlled in diameter, space and thickness, have potential applications in photoelectronic devices, sensors, solar cells and nanometer devices.

Abstract: The barium titanate nanopowder was widely applied to many fields because of its excellent performances. The homogeneous barium titanate nanosized powder with high purity and small size was achieved by sol-gel. Effects of different amount of the hydrolysis of acetic acid solution on gelation process and particle size of the powder, PH value on gel time and heat preservation temperature on gelatinization were studied in the paper. The amount of the hydrolysis of 36% acetic acid solution was 25ml and the amount of Glacial acetic acid used for PH adjustment was 25-30ml. The heat preservation temperature was 95-100 °C.

Abstract: Using Er (NO₃)₃·5H₂O and Fe (NO₃)₃·9H₂O as major materials, the ErFeO₃ nanoparticles were prepared by successive microwave processing and high temperature calcination. The samples were characterized by thermogravimetric and differential thermal analysis (TG-DTA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible diffuse reflectance spectroscopy (DRS). It was found that the single phase ErFeO₃ can be obtained through the calcination of microwave processed ErFeO₃ precursors at 800°C, and the resulting product was approximation flake of 20-80 nm. The visible-light photocatalytic activity of ErFeO₃ nanoparticles was investigated in experimental simulation wastewater containing 10 mg/L methyl orange (MO). The results show that ErFeO₃ nanoparticles appear high photocatalytic activity for the decomposition of MO under visible-light irradiation.

Abstract: Materials combined with a small amount of nanomaterials offer new possibilities in developing of multifunctional composites. Nanocarbon materials (NCMs) such as carbon nanotubes/ nanofibres, and nanographite platelets have excellent intrinsic physical properties and improvement effect to matrix materials at nanoscale. They are promising fillers for improving the mechanical property and durability of cement-based materials and introducing functional properties to cement-based materials. This paper presents a comprehensive introduction about multifuntionlities of NCMs filled cement-based composites including mechanical properties, durability, electrical properties, thermal properties, electromagnetic properties, sensing property and etc.

Abstract: Due to high reaction activity and high combustion heat release, magnesium is widely used in the field of explosives. The research focus of this article is the effect of magnesium powder size and content on the thermal decomposition of PTFE. Two different particle sizes of magnesium powder are regarded as research objects. The thermal behavior of Mg/PTFE energetic system was investigated by TG-DSC analyzer. The experimental results show that magnesium has a catalytic effect on the thermal decomposition of PTFE. With the increase of magnesium content , the decomposition peak temperature of PTFE decreased firstly and when passed the ratio 50% increased, the best mixing ratio is Mg: PTFE =50:50. Within nanopowder, the activation energy of PTFE decreased by 150kJ∙mol^-1 compared to 112 kJ∙mol^-1 by mixing with micro powder. Obviously nanopowder has a better reactivity than micro powder, so has a more obvious catalytic effect.

Abstract: Nano-TiO₂ Modified Fluorine-Containing Polyacrylate Soap-Free Emulsion was Successfully Synthesized via Soap-Free Emulsion Polymerization Technique, in which the Polymerization Monomers Consisted of Methyl Methacrylate (MMA), Butyl Acrylate (BA) and Dodecafluoroheptyl Methacrylate (DFMA). the Influence of Amount of Initiator, Emulsifier, Containing Fluorine Monomer and nano-TiO₂ on the Performance of Emulsion was Investigated. the Results Showed that the Good Polymerization Stability, and High Monomer Conversion were Obtained when the Amount of Ammonium Initiator was 1.2%, the Amount of Reactive Emulsifier was 3.5%. with Increasing Amount of DFMA, the Monomer Conversion Decreased and the Gel Rate Increased Gradually with the Increase of DFMA Amount. UV-Blocking Ability of the Cotton Fabric Treated with the Hybrid Emulsion Containing Nano-Tio₂ increased with Increasing Amount of Nano-TiO₂. IR Spectrum Results Showed that Nano-TiO₂ and Fluorine-Containing Monomer were Successfully Introduced in the Segmental Structure of the Polymer. SEM Revealed that Nano-TiO₂ was Loaded on the Surface of the Treated Cotton Fabric which had Good Hydrophobicity.

Abstract: Hydrophobic polyurethane (PU) sponge for oil absorption application was fabricated by ZnO nanomaterial coating and stearic acid modification on ZnO surface. The contact angle and oil absorbent capacity ability of the obtained sponge were measured. It was demonstrated that both ZnO nanoparticle and ZnO nanorod coated PU sponge (ZnO NPs-PU and ZnO NRs-PU) showed good hydrophobicity and oil absorbent ability. ZnO NPs-PU and ZnO NRs-PU sponges have absorbent capacities of 18~92 times and 20~98 times of their own weight for different organic liquids, respectively. Moreover, the absorption capacity of the ZnO NRs-PU sponge did not deteriorate over 50 cycles. Therefore, the ZnO NRs-PU sponge has excellent recyclability for future application.

Abstract: Epoxy resin presents 3D cross-linking network structure characteristics after curing, resulting in a lower wear resistance of epoxy resin, which limits its extensive applications. In this paper, the effects of adding carboxyl functionalized carbon nanotubes on the tensile strength and wear resistance of carbon nanotube/epoxy composites were studied. The results showed that the tensile strength and wear resistance of the composites were effectively improved through carboxyl functionalization of carbon nanotubes.