Advanced Materials Research Vols. 463-464

Abstract: The surface and structural properties, thermal stability and oxygen storage capability are inverstigated in ceria-zirconia-alumina oxide with deposition coprecipitation method using the Pseudoboehmite precursor. X-ray diffraction (XRD), Brunauer-Emmet Teller method (BET), Transmission electron microscopy (TEM) and oxygen pulsing technique are used to character the prepared materials. The prepared ceria-zirconia-alumina oxides are highly dispersed composite solid solution. After calcination at 650 °C and 1000 °C respectively, these compounds can still keep the structural and textural stability and hold excellent oxygen storage capability.

Abstract: The ion-exchanger Al1.6667Ti(PO4)3 of inverse spinel type was prepared by means of the solid state reaction crystallization method. Its ion-exchange properties for alkali ions such as saturation capacity of exchange and distribution coefficient were determined. Al1.6667Ti(PO4)3 was characterized by virtue of X-ray diffraction method. This inorganic ion-exchanger has the saturation capacity of exchange for Li+ higher than those for other alkali ions, the saturation capacity of exchange for Li+ reaches to 6.6mmol/g.

Abstract: The rapid transit railway foundation bed bears the repeated dynamic load of train besides the static-load from upper structure. The engineering characteristics of improved clay, in especial the dynamic performance under repeated dynamic load or train, is the key factors to determine the improved clay can be used as roadbed fill material. In this paper, the dynamic triaxial test is adopted to imitate the repeated load of train, and the engineering characteristics of improved clay is studied such as dynamic stress plastic strain and elastic strain etc. which influence the running seriously.

Abstract: The effect of the plies number and the thickness on flexural properties of glass fiber reinforced polyester or epoxy composites has been investigated experimentally. Laminates were fabricated by hand layup technique in a mould under light pressure and followed by curing at room temperature for 8 hours. Laminates were made with a different number of plies, by varying the number of glass layers and the thickness so as to obtain different total fiber weight fraction. Tests were conducted on a hydraulic universal testing machine, Zwick Roell type 50 kN capacity, using automatic data acquisition software. The results indicated that the plies number and the laminate thickness have a great effect on flexural properties. An overall comparison between the flexural properties of all the laminates which have the same design revealed that the glass/epoxy laminates have better properties than those of glass/polyester laminates. It is found that the behavior of these laminates is dominated by damage mechanisms such as delamination, buckling and fiber rupture.

Abstract: A series of blends have been prepared by adding a novel thermoplastic poly (phthalazinone ether sulfone ketone) (PPESK) in varying proportions to diglycidyl ether of bisphenol A epoxy resin (DGEBA) cured with p-diaminodiphenylsulfone. The kinetics of curing reaction and glass transition temperature (Tg) of PPESK/DGEBA blends were performed using differential scanning calorimetry (DSC) technique. It is proved that the addition of PPESK accelerated curing reaction and resulted in great enhancement of thermal properties of the blends. There was moderate increase in the fracture toughness as estimated by the critical stress intensity factor (KIc). Compared to that of unmodified epoxy, the maximum toughness of the modified blends had increased 32% by addition of 15 phr PPESK. Fracture mechanisms such as crack deflection and branches, ductile microcracks, ductile tearing of the thermoplastic of the matrix were responsible for the increase in the fracture toughness of the blends

Abstract: Compound Al2.6667Ti(PO4)4, a inverse spinel-type metal compound, was prepared by a solid state reaction crystallization method. The Li+ extraction/inserti on with this material were investigated by X-ray, FT-IR spectroscopy, and Kd measurement, The chemical analysis showed that the Li+ extraction insertion be progressed mainly by an ion-exchange mechanism. The acid treated samples had an ion exchange capacity of 8.0mmol/g for Li+. It had a memorial ion-sieve property for Li+.

Abstract: Maghemite (γ-Fe_{Subscript text}2O_{Subscript text}3) and hematite (α-Fe2O3) nanoparticles with various dominant exposure crystal planes were prepared by several different methods. The structure and the reducibility of these materials were investigated by XRD, Raman and H2-TPR technologies, and their catalytic performance for propene oxidation was also discussed. The maghemite (γ-Fe_{Subscript text}2O_{Subscript text}3) showed a better reducibility than hematite (α-Fe_{Subscript text}2O_{Subscript text}3), but its activity for propene oxidation is relatively lower. The exposure crystal plane of hematite has a significant influence on its catalytic activity for propene oxidation. Among the prepared four samples, the hematite-1 sample showed the best activity. The selective growth of any planes with a relative low density of Fe atoms for the α-Fe_{Subscript text}2O_{Subscript text}3 catalyst would lead to an obvious decrease in the catalytic activity.

Abstract: Adsorption behavior of Rhodamine B (RhB) onto thermal modified rectorite (TM-R) has been thermodynamically investigated. The thermal modified rectorite prepared at different temperatures was characterized by X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET). The analysis of the isotherm equilibrium data using the Langmuir and Freundlich equations by linear methods showed that the data fitted better with Freundlich model than the Langmuir model. Thermodynamic parameters were calculated based on Van’t Hoff equation. The average change of standard adsorption heat of RhB was 88.96 kJ/mol. The adsorption Gibbs free energy changes are in the range of -26.88～-34.52 kJ/mol, The negative of adsorption Gibbs free energy changes in all cases are indicative of the spontaneous nature of the adsorption interaction, and the values of adsorption entropy changes are positive.