Advanced Materials Research Vol. 893

Abstract: The viscoelasticity and orthotropic of composite materials has been investigated. Based on the essence of dynamic wave equation, a numerical modeling of guided waves propagating in anisotropic viscoelastic plates is developed by employing the spectral finite element method (SFEM). The phase velocity, energy velocity and attenuation curves can be obtained and analyzed by simulating carbon-epoxy film and carbon-epoxy film on the different substrates. The results illustrate that the mode coupling phenomenon will occur due to consider viscoelastic of composite materials which can use for choice of frequency. In the viscoelastic film/substrate system, the more modes and the lower attenuation amplitude appear which explains the better for monitoring long distance. Knowledge of these properties is important for evaluating material damage and designing material structure .

Abstract: A benefit of imprinted polymers is the possibility to prepare sorbents with selectivity pre-determined for a particular substance, or group of structural analogues. The application most close to a wider acceptance is probably that of solid phase extraction for clean-up of environmental and biological samples. The technique of molecularly imprinted polymers to solid phase extraction (MISPE) is performance and high selectively, compared with traditional sorbents. In this paper, the preparation and application of MIPs would be reviewed.

Abstract: Different hyperbranched polyester were synthesized by a simple one-pot melt polymerization method.The acid value,hydroxyl value and NMR were detected, we discussed the effect of proportion of DMPA,reaction temperature, vacuum level and vacuum time on acid value, hydroxyl value.The results show that the high efficient hyperbranched dispersant can be synthesized by the mass ratio of DMPA is 42.14%, vacuum time is 6h, vacuum degree is 30 kPa, and the stability kinetic is under 0.2.

Abstract: The β nucleated polypropylene (PP), uncompatibilized β nucleated PP/polystyrene (PS) and compatibilized β nucleated PP/PS blends were prepared on a twinscrew extruder.and added into compatibilizers styrene-ethylene-propylene block copolymer (SEP) or two styrene-ethylene-butylen- e-styrene block copolymers (SEBS) with different content of styrene.The crystallization characteristic, melting behavior and crystallization kinetics of these composites were studied.

Abstract: To study the effect of doping cerium oxide on the microwave absorbing properties of Polyaniline /Al-alloy foams, the surface of Al-alloy foams was coated with Polyaniline (denoted by CfP),and doping 1%, 2%,5% (mass percent) cerium oxide (denoted by CfP1,CfP2,CfP5) of Polyaniline respectively. The coated Al-alloy foams were tested according to the Standard GJB 2038-94 Method to test the reflectivity of radar absorbing materials, i.e., the RCS (radar cross-section) method. The morphology and distribution of microwave absorbent were analyzed by scanning electron microscopy (SEM) and X-Ray Diffractomer (XRD).The absorbing properties of each example under different wave band were discussed. The results indicated that in the 12~18GHz and 26.5~40GHz bands the absorbing properties increase with the increase of frequency, and after doping the rare earth oxide, the absorbability of the composite material was enhanced.

Abstract: A phosphorescent iridium in the poly (fluorene) was synthesized and characterized by UV-Vis absorption and luminescence properties. The highly thermal stable was investigated by TGA. The result shows that the polymer could be a good candidate in PLED device.

Abstract: This paper presents an introduction to the approach to calculation of fractal dimension of SiO₂/UPR granular composites. The porosity of quartz mixture, the density, the optimum amount of unsaturated polyester resin (UPR) and the mechanical properties of the SiO₂/UPR granular composites were tested. The relationship between the four factors and the fractal dimension was analyzed and the relation expressions were obtained by fitting. For the SiO₂/UPR granular composites, fractal theory is not only used for the design of gradation and the optimum amount of UPR, but also for calculating and evaluating the mechanical properties. Research shows that the fractal dimension plays a role of linking the microstructure and the macroscopic properties of the SiO₂/UPR granular composites.

Abstract: This paper discusses the influence of die temperature on the solidification behaviour of A356/SiC_p composites fabricated by squeeze casting method. Information on the solidification studies of squeeze cast composites is somewhat scarce. Experiments were carried out by varying the die temperatures for cylindrical shaped composite castings K-type thermocouples were interfaced to the die and the temperature-time history was recorded to construct the cooling curves. The cooling curves are also predicted from the finite element analysis (FEA) software ANSYS 13. The experimental and predicted cooling curves are not in good agreement. In addition to, the experimental and theoretical solidification times are studied. It was understood that the increase in the die temperature decreases the cooling rate.

Abstract: In this paper, the ignition performances of the titanium composite Semiconductor bridge (Ti SCB) and the polysilicon semiconductor bridge (PSCB) were studied, which include electrical explosion characteristics, temperature of theplasma generated by those two SCBs, and ignition ability with B/KNO₃. The experiment results indicated that the explosion time of the two kinds of SCB both decreases with increasing input energy. The temperature of the plasma generated by the two kinds of SCB both increases with the increasing input energy, and there is no significant difference in the highest temperature under the same condition. And the ignition experiment indicated that the output energy of Ti SCB is lower than PSCB.

Abstract: Composite cathode La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ-SDC carbonates (LSCF-SDCC) for applications of low temperature solid oxide fuel cell (LTSOFC) were developed. LSCF-SDCC were mixed using high energy ball milling technique via dry and wet milling method followed by calcinations at 700, 750 and 800 °C. The findings reveal that different calcinations temperature and milling techniques gives effects to the composite cathodes powder. Clear peak intensity demonstrate from wet milling technique as confirm via XRD analysis indicates that crystalline structure has been improved. FESEM investigation demonstrate the presence of large particles in the resultant powder resulting from the increased calcination temperature. LSCF-SDCC composite cathodes powder produced via wet milling technique have good fine fraction and demonstrates good crystallite structure to be served as cathode of LTSOFC compared to dry milling technique.