Advanced Materials Research Vols. 734-737

Abstract: Nickel and antimony doped tin oxide (NATO) electrodes were prepared by sol-gel dip-coating method. The effect of doping levels was investigated via scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The electrochemical ozone generation efficiency was also tested. The results showed that sol-gel prepared electrodes had a smoother surface morphology and lower current efficiency for ozone generation than electrodes prepared by traditional pyrolysis method. The nickel and antimony doping lead to a decrease in the crystallites size, while its effects on ozone generation efficiency were complex.

Abstract: Three salen complexes N,N'-bis(salicylidene)-1,2-phenylenediamino MⅢ Cl were prepared and employed for the copolymerization of carbon dioxide with propylene oxide. FT-IR and UV-Vis spectra confirmed the characteristic of metal salen complexes obtained. The central metal atoms in the salen complexes have great influence on the copolymerization of carbon dioxide with propylene oxide. The result shows that chromium metal is more effective to synthesize PPC copolymer. The structure of the resulting PPC was characterized by IR 1H NMR and GPC. 86.3% carbonate content of the PPC was achieved with chromium salen complexes.

Abstract: Lanthanum doped TiO₂ powders were prepared by hydrolysis of titanium tetra-n-butyl oxide and La (NO₃)₃ in solution. The resulting powders were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis absorption spectroscopy. The photocatalytic activities of doped samples were evaluated by the decomposition of methylene blue under visible light irradiation. The XRD results showed that the doping of lanthanum could not only efficiently inhibit the grain growth but also suppress the phase transition of anatase to rutile. UV-Vis spectroscopy of lanthanum doping TiO₂ indicated that the absorption onset red-shifted to the visible light region. XPS results revealed that La₂O₃ had formed which could enhance the surface area. The degradation rates of methylene blue verified that the visible light photocatalytic activity of TiO₂ has been enhanced by the doping of lanthanum.

Abstract: A new magnetic Fe₃O₄/MO-intercalated-LDH composite has been synthesized by combination of Fe₃O₄, layered double hydroxide (LDH) and methyl orange (MO). Fe₃O₄/Zn₂CrLDH and Fe₃O₄/MO-intercalated-LDH were obtained via two-step microwave hydrothermal and anion exchange method. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and vibrating sample magnetometer (VSM) were conducted to characterize the as-prepared samples. The latter exhibited that basal spacing of Zn₂Cr-LDH is 1.18 nm. The value of saturation magnetization (M_s) is 20.5 emu/g. In addition, the amounts of adsorbed MO reached 1.54 mmol/g. Therefore, the material shows several advantages for the removal of pollutants.

Abstract: Poly (vinylidene fluoride) (PVDF) hollow fiber membranes were successfully prepared using DMAc/γ-BL as the mixed diluent and PEG as the additive through modified thermally induced phase separation (M-TIPS) process. The membranes prepared were characterized by scanning electron microscope. Their properties such as water permeability and mechanical properties were also determined. The results show that PVDF membranes have spherical crystallites structure with interconnected network structure because of the combination of solidliquid and liquid-liquid phase separation. When using 25wt% aqueous ethanol solution as the coagulation, the PVDF hollow fiber membrane shows the tensile strength, i.e.4.59MPa and pure water flux, i.e.415 L/ (m²·h).

Abstract: Two component self-healing microcapsules were prepared by in situ polymerization with poly (melamine-urea-formaldehyde) as wall, epoxy resin and latent curing agent sebacate hydrazide as core. The ratio of two core material and the reaction process were studied. The size and distribution of particle, surface morphology, structure, thermal properties and content of core were measured and characterized by using particle size analyzer（PSA）, optical microscopy (OM), infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA). The results showed that the microcapsules have smooth and compact surfaces, and have spherical profiles. The average diameter of microcapsules is 30μm and core content of microcapsules is 70%. The heat resistance and solvent resistance of microcapsule are better. The curing temperature is 190°Cand the healing efficiency can be improved.

Abstract: The graphite intercalation compound with easy low temperature exfoliated and high exfoliated volume was prepared by chemical oxidation method using natural graphite flakes, C₂H₅COOH, FeCl₃ and CrO₃ as raw materials, according to the mass ratio of 1:2.8:0.3:0.2. The expansion volume of gra_{Subscript text}phite intercalation compounds was 320 mL•g^-1 at 300°C and achieved biggest 580 mL•g^-1 at 700°C. The composition, structure and properties of the graphite intercalation compound were characterized and analyzed by SEM, FTIR, XRD, TG, DSC, VSM techniques. Results showed that the intercalant of graphite sandwich were C₂H₅COO^- and FeCl₃.

Abstract: The PVB/ β-CD/silica nanofiber in the ratio of β-CD:PVB=1:3 and doping 5% nanosilica was fabricated by electrospinning techniques at 18 kV of the applied voltage. The morphologies and structures of PVB/β-CD/silica nanofibers were investigated by scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), energy dispersive spectrometer (EDS). Chimb-shaped PVB/β-CD composite nanofiber was observed by SEM. The FTIR results showed that β-CD is present in PVB fiber matrix. EDS analyses of PVB/β-CD and PVB/β-CD/ silica nanofibers reveal the presence of Si in PVB/β-CD/ silica nanofiber.

Abstract: In this study, flame retardant microcapsules were synthesized using magnesium hydroxide as core materials, melamine resin as the shell material. The structure, diameters and thermal properties of prepared microcapsules were investigated by using FTIR, ELS, DSC and TGA. The effects of core/shell ratio on the properties of microcapsules were studied.Flame retardant materials of low-density polyethylene/magnesium hydroxide microcapsules were prepared.The tensile strength and elongation at break tests were performed to determine its mechanical property.Inflammability of the materials was also studied.The results showed the prepared magnesium hydroxide microcapsule shows good thermal stability and it has free compatibility with the polymer.The composites of HDPE/MH microcapsules have good performance．

Abstract: Magnesium and its alloys, which have excellent biocompatible and biodegradable properties, are potential materials in biomedical application and studied by more and more researchers in recent years. However, due to the poor corrosion performance, the clinical applications of magnesium and its alloys are greatly limited. The surface coating is one of the effective means to solve this problem. This paper reviews recent work on surface coating of magnesium and its alloys as biomedical materials and discusses the corrosion resistance and biocompatibility of modified materials. The future development trend in this field is also proposed.