Advanced Materials Research Vols. 573-574

Abstract: Grafting copolymerization method was used to synthesize copolymer of polyethylene with single-walled carbon nanotubes (SWNTs). Firstly, SWNTs were functionalized along their side walls with 1-alkene organic groups using the 1, 3-dipolar cycloaddition reaction. Then, a metallocene catalyst C2H4[(tert-H)Ind]ZrCl2 was used to synthesize polyethylene grafted from SWNTs (PE-g-SWNTs) copolymers by copolymerization with ethylene. SWNTs can be used to compound PE-g-SWNTs nanocomposites by a grafting copolymerization approach. The results show that PE covalently grafted from organic functionalized SWNTs forming a strong interface between the SWNTs and the PE matrix. The microstructure of the obtained copolymers was characterized. The SWNTs were dispersed well in the copolymers due to covalent linkage of functionalized SWNTs with polyethylene. Thermal stability of PE-g-SWNTs is better than those of pure PE and PE/SWNTs physical mixture. It indicates that the addition of SWNTs by the grafting copolymerization approach is mainly due to the delay of the thermal decomposition temperature in PE matrix.

Abstract: As a result of testing the large number of organic liquids, it was established that benzyl alcohol is the most suitable medium for the reduction of nickel compounds. This is a monohydric aromatic alcohol; its composition is described by formula С6H5−CH2−CH2OH. Benzyl alcohol has not very high boiling point (205 °C), the catalytic activity of nickel is low under these conditions, so the negative consequences of dehydrogenation become noticeable only if the process duration is tens hours. At the same time, the reducing potential of benzyl alcohol turned out to be rather high. In application of nickel carboxylates, the time of complete reduction did not exceed 3-4 hours, which allowed us to obtain high-purity nickel powders. Further development of the investigation showed that benzyl alcohol can be successfully used also to reduce the salts of other metals: copper, bismuth, silver, cobalt.

Abstract: This paper analyzes the adaptability of process of alloy structural steel 50Mn2V by simulating research. Through the high temperature tensile test、the multi-pass deformation test we study the deforming resistance characteristics of 50Mn2V steel, and carry on the contrast with high strength steels P20（3Cr2Mo）of a factory; Through thermo-plasticity test the high temperature thermoplastic of 50Mn2V steel is studied. The test result indicates a factory has ability to produce the high strength 50Mn2V steel completely with present equipment.

Abstract: This paper analyzed the HSLA pipeline steel’s stress corrosion behavior and mechanism which tested in the saturated solution of H2S. The steel’s SSCC susceptibility was determined by constant load tensile according to NACE TM-0177 standard. Used SEM observed the fracture, and then the steel’s corrosion rate and short-term corrosion behavior were analyzed by electrochemical polarization curves in saturated solution of H2S in the environment A. The results show that the steel has a large SSCC susceptibility and a high corrosion rate. What’s more, corrosion rate increases with the increase of immersion time. The results also show that the crack fracture of the steel is caused by anodic dissolution and the hydrogen which penetrates into the steel can increase the anodic dissolution.

Abstract: According to two parameters combination of the material thickness and air-gap depth, from the angle of pure optimization, this paper obtained the optimal parameters of single cavity and double cavity structure by using the simulated annealing algorithm for single cavity and double cavity of aluminum foam sound absorption structure of systematically optimization design at 100-4000HZ frequency band. Finally, studying effect of increasing the number of cavity on aluminum foam sound absorption properties.

Abstract: Al2O3-glaze composite ceramic coating was prepared with enamel coating as transition layer and Al2O3 as hard antiwear facies on Q235A steel surface in this paper, and the effects of the particle size and volume fraction of ceramic coating on erosive wear behavior of composite coating were investigated. The results show that enamel performance of ceramic coating is better when the particle size of glaze is 16µm; the anti-wear property of composite ceramic coating is improved by adding Al2O3 particle, and the coating with 50μm particle size and 40% volume fraction particles, eroded at 45° impact angle at 15MPa pressure, is the best, which is 4.2 times than that of the enamel coating without Al2O3.

Abstract: The development of new electrode materials with high storage capacity is indispensable for improving rechargeable lithium batteries. Herein, high performance TiO2 microspheres have been fabricated by a facile solvothermal method. The obtained TiO2 microspheres were investigated by the measurements of X-ray diffraction pattern, scanning electronic microscopy, and electrochemical tests. As the rates increase from 1C to 20C, the TiO2 composites display high discharge capacities of 414.6 mAh g-1 for the first cycle at 1 C and 244.6 mAh g-1 at 20 C over 100 cycles. CV experiments indicate that there are two peculiar pairs of cathodic/anodic peaks occurred in the range of 1.0-3.0V, which clearly demonstrates that the structure of the TiO2 microspheres here is quite different from the ordinary anatase TiO2. Excellent rate capability and cycle ability are ascribed presumablely to the unique structure.

Abstract: San Yang Gang tidal sluice gate is easily to produce temperature crack at early age because of the use of pump hydrotechnic high performance concrete in the constructing process. Based on the analysis of parameters of three-dimensional temperature field and temperature stress field, comprehensive measures which are consist of lower inside temperature through cooling water pipes , keep the outer surface moist, increase temperature distribution bars, reduce pumping concrete slump and mixing polypropylene fiber were proposed. These comprehensive measures have solved the problem of temperature control and crack prevention successfully.

Abstract: This work introduced electrochemical parameter etched surface current intensity to mainly study corrosion fatigue life of aluminum alloy 7075 under stress control. The S-N curve of 7075 was obtained in specified corrosion media, and a new model was proposed to predict corrosion fatigue crack initiatio.

Abstract: Flax yarn and PP filament can be made into flax/ pp lapping yarn. Weaving with the lapping yarn, and finally can crank the fabric into PP/ flax composite by hot pressing. Research on the thickness of composite material and the peeling properties of the composite material, we analyzed the correlative factors about the producing technics of composite by orthogonal experimental method. The results showed that the material’s thickness and the technics are the main influencing factors of the wettability, and forecast the technics of composite molding process to get the best wettability properties.