Advanced Materials Research Vol. 904

Abstract: This paper explained the general performance requirement of astronautic structural material at the first, then introduced the fundamental characteristics and application of widely used astronautic structural material, analyzed on emphasis the application status of the metal materialcomposite materials and thermal protective materials,at the end of the paper, the development demand in the future of astronautic structural material Was pointed out .

Abstract: Nonlinear finite element method is used in this paper to research the ultimate strength characteristics of aluminum stiffened plates under uniaxial tension-compression cyclic loading. This paper focused on the effect of the distribution mode of HAZ, the range of HAZ and different cyclic loading process on the ultimate strength of aluminum stiffened plates. The results obtained have a certain reference value to the design and manufacture of aluminum stiffened plates.

Abstract: Ultraviolet (UV) curable waterborne polyurethane dispersions with comb branched structure were synthesized by prepolymer process. C=C bonds were incorporated into the branched chains of the polyurethane using chain extender, hence, the content of C=C bonds can be adjusted by the chain extender consumption. The chemical structure was identified by Fourier transform infrared spectroscopy (FTIR) and ¹H NMR. Effects of the chain extender content on the microstructure, rheological behavior, thermal property, mechanical and other properties of the UV cured films were researched.

Abstract: The TiO₂ nanotube array film was synthesized on the surface of Ti-Nb-Zr-Mo βTitanium alloy via anodic oxidation in single electrolytic solution only containing HF. The diameter of TiO₂ nanotubes was 30-50nm, and the length was 240nm. Compared with the processing parameters (including anodizing voltage, reaction time, concentration and kinds of electrolytic solution) used for pure Titanium or Ti-6Al-4V alloy, the parameters was further optimized. The surface morphology and element compositions Ti-Nb-Zr-Mo alloy before and after anodic oxidation were observed and analyzed by a scanning electron microscope (SEM) and an energy dispersive X-ray (EDX) spectrometer. The antibacterial property of TiO₂ nanotube array film prepared with optimal conditions was evaluated by coculture in vitro between Actinomyces viscosus and materials tested. The results indicated that the TiO₂ nanotube array film had very good antibacterial activity to resist Actinomyces viscosus. TiO₂ nanotube array film/Ti-Nb-Zr-Mo βTi alloy biocomposite will be an more excellent dental implant owning good biomechanical adaptability, biocompatibility and antibacterial property.

Abstract: Polypyrrole/Graphene oxide composite material (PPy/GO) was synthesized using an in-situ chemical polymerization method. The formation of composite had been shown by the analysis of Fourier transfer of infrared spectroscopy and X-ray diffraction data. Scanning electron and transmission electron microscopy clearly showed sheet-like layered structure of graphite oxide surrounded by polypyrrole. Electrochemical properties were characterized by electrochemical station. We demonstrated the intercalation of conducting polypyrrole into the graphite sheets, and that as electrodes for supercapacitor, the PPy/GO composites (GO_0.54) with PPy to GO mass ratio of 5:3 showed a competitive capacitance of 337 F g^-1 at a scan rate of 2 mV s^-1 than that of PPy alone. Given the electrical and electrochemical properties, we prospect that the PPy/GO composites should find applications in supercapacitors.

Abstract: The graphene oxide/Fe₃O₄ composites were prepared by in situ precipitation method in this article. The microstructure and surface morphology of composites were characterized by Fourier transform infrared spectrum, X-ray diffraction and scanning electron microscopy, respectively. Cyclic voltammetry was employed for the determination of specific capacitance and other electrochemical performances. It was shown that there was the chemical bonding force between GO and Fe₃O₄ particles. And the surfaces of GO were wrapped by the Fe₃O₄ particles precipitated on the surfaces of GO sheets and no impurities were detected. Furthermore, the specific capacitance of GO/Fe₃O₄ composite electrodes decreased as Fe₃O₄ particles reduced and the redox peaks became weaker owing to the addition of nonconductive Fe₃O₄ particles.

Abstract: This study aimed to understand the effect of a binder on the wear performance of HVOF WC-based coatings. Three kinds of commercial feedstock powders were studied, i.e. WC-12Co, WC-10Co4Cr and WC-10Ni. Characterization was conducted using SEM, micro Vickers hardness test and XRD. It was found the WC-10Co4Cr coating showed the highest hardness, while the WC-10Ni coating the lowest. The WC-10Co4Cr coating showed very good wear resistance as compared with the widely used WC-12Co coating.

Abstract: Functional floating bead (F-FB), prepared by anchoring the organic sulfonic acid on the surface of the blackberry-like structural FB, was used as both the inorganic substrate and the in situ dopant for the in situ chemical oxidative polymerization of pyrrole to obtain the plypyrrole/functional floating bead (PPy/F-FB) nanocomposite material. The composites possess high electrical conductivity at room temperature. Thermogravimetric analysis shows that the thermal stability of PPy/F-FB composites was enhanced and these can be attributed to the retardation effect of sulfonic acid-functionalized FB as barriers for the degradation of PPy. The morphology of PPy/FB composites showed the well-defined blackberry-like morphology.

Abstract: A simplified and efficient method was developed for the large-scale purification of the epothilone A and B from fermentation products of Sorangium cellulosum after organic solvent extraction in this paper. Extractant from XAD-16 resin with tetrachloromethane containing epothilones was concentrated under vacuum, subjected to Sephadex LH-20 column chromatography, and eluted with several solvents. Fractions containing epothilones are pooled, concentrated, and applied to a second cycle of column chromatography with other solvents. Result showed that elution with acetone gave the best purity of epothilones [78.1% by high-performance liquid chromatography (HPLC) than that with pure methanol, pure ethanol, 70% (v/v) aqueous methanol or methanol-dichloromethane (1:1, v/v).] Then, when flow rate was 0.2 mL/min and sample amount (epoA) was 1 mg in second cycle, elution with methanol was resulted in complete separation between epothilone A and B, and further improved separately the purity of epothilone A and B to 90.27% and 77.34%. This simplified purification scheme avoided the loss of expensive epothilones in the common silica gel separation process and achieved the separation of epothilone A and B, significantly reduce the cost of the production without preparative liquid chromatography, or other equipment.

Abstract: In this paper, under the effect of MD1041 cashew oil modified phenolic amine curing agent for epoxy resin, it successfully prepared polyurethane flexible resin modified epoxy resin composite materials by using polyurethane modified epoxy resin reinforced flexible resin. Modified composite material of the new preparation is characteristed by the method of the mechanical performance test, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC). The results show that the flexible resin has a strong effect on the toughness of modified epoxy resin composite materials. When the mass ratio of the flexible resin account for 5.9%,comprehensive mechanical properties of the modified composites is at the premium; when the mass ratio of flexible resin account for 3.1%, the thermal stability of the epoxy resin modified with flexible resin is at the best.