Advanced Materials Research Vols. 391-392

Abstract: Lignin has been blended with low density polyethylene (LDPE). Maleic anhydride grafted high density polyethylene (HDPE-g-MAH) and Maleic anhydride grafted polypropylene (PP-g-MAH) have been added as compatibilizing agent. The weight ratio of LDPE, ligin and HDPE-a-MAH were 75:25:7.5, 75:25:10 and 75:25:12.5; the weight ratio of LDPE, ligin and PP-a-MAH were 75:25:5, 75:25:7.5 and 75:25:10 respectively. The mechanical properties of the blends were investigated according to Chinese standard GB/1447-2005 and compared with those of lignin/LDPE composites without compatibilizing agent. Scanning electron microscopy (SEM) was used to investigate the dispersion of the lignin and PE and the compatibilizing mechanism was analyzed. The results reveal that addition of compatibilizing agent increased the interfacial bonding strength of the composites, improved the mechanical properties and obtained the better dispersion of the lignin and LDPE with HDPE-g-MAH as compatibilizing agent.

Abstract: Hydrogen silicone oil was used as an intercalation agent to treat Na⁺-montmorillonite, and thus organic montmorillonite (OMMT) was obtained. RTV/OMMT composites were prepared by these organic-clays and RTV. The tensile strength, hardness, and thermal properties of these composites were investigated. The structure and morphology were verified by SEM and XRD analysis. Results showed that RTV/OMMT-3% composites had the best tensile properties.

Abstract: Rare-earth (RE)-doped TiO₂ photocatalysts were prepared by doping samarium ions into TiO₂ nanoparticles in a sol-gel process. The samples were characterized using X-ray diffraction (XRD). Their photocatalytic activities were evaluated by photodegradation of methyl orange (MO) in water under UV light irradiation. Finally, influences of rare-earth ions doping on the structure and photocatalytic activity of TiO₂ were studied using grey correlation analysis method based on multi-variable grey model. The experimental results indicated that the doping modifications of TiO₂ work through the structure change in nanoscale, leading to the change of activities. It was also found that the main actors influencing on activity of RE-doped TiO₂ are crystalline size (D) and crystal constant (a) for the MO photodegradation base on the grey relational analysis method. Using the same method above, the activities of RE-doped TiO₂ photocatalysts could be predicted and doping concentration need to be optimized.

Abstract: Both transient-state and steady-state interfacial tension (IFT) between anion Gemini surfactants solution and crude oil were measured. The effects of various parameters such as anion Gemini surfactant molecular structure, concentration, category of crude oil and salinity of water medium on the interfacial tension between crude oil and water were investigated in detail. The results reveal that when the length of the carbon chain or the carbon number of spacer is constants, the increase of either carbon number of interval groups or length of carbon chain is favorable to decrease the interfacial tension. AN12-4-12 has the lowest interfacial tension. As the concentration of anion Gemini surfactant increasing, the interfacial tension between crude oil and water decreases. Anion Gemini surfactants which have a larger carbon number of interval group and longer hydrophobic carbon chain have a better interfacial activity. AN12-4-12 has the best interfacial activity. When the concentration of AN10-4-10, AN12-4-12 reaches up to 2000 mg•L^-1, it can lower the steady-state oil-water IFT to 10^-3 mN•m^-1. Different kinds of crude oil have different effects of decreasing IFT and different interfacial activity for the same anion Gemini surfactant. The Critical Micelle Concentration (352mg•L^-1, 487mg•L^-1) of AN8-4-8 and AN12-4-12 between thin oil and water interface is obviously lower than those (1000mg•L-1, 3000mg•L^-1) between mixed heavy oil and water interface. But molecular structure still has a larger influence on interfacial tension than category of crude oil. The IFT between AN12-4-12 solutions and mixed heavy oil lower an order of magnitude than that between AN8-4-8 solutions and mixed heavy oil. As the solution salinity increased, the interfacial tension between anion Gemini surfactant solution and thin oil decrease rapidly. The longer the hydrophobic carbon chain is, the more obvious the effect of salinity is. The salinity is not less than 1.2×10⁵ mg•L^-1, AN12-4-12 can decrease the oil-water interfacial tension to 2.2×10^-3 mN•m^-1, while AN8-4-8 only makes that reduce to 9.7×10^-3 mN•m^-1.

Abstract: According to the particularity of the autoclaved cement concrete that partial aggregate could participate in hydration reaction in the process of autoclaving, the optimal gradation of coarse aggregate and the optimal slurry aggregate ratio is studied, and the effect of water reducing agent for fluidity of cement paste is also studied. The optimized mix design of autoclaved cement concrete based on high strength (compressive strength and flexural strength) is done by orthogonal test with four factors (water-binder ratio, type of mineral admixture, amount and sand ratio) and four levels.

Abstract: 0.2-mm-thick copper and 0.3-mm-thick nickel-plated steel dissimilar metals were jointed by resistance spot microwelding. The processing parameters were optimized by orthogonal experimental and influence of processing parameter on the morphology and microstructure of welded joint was studied. The results show that the optimized processing parameters that can get the maximum tensile-shear force are: preheat current is 0.8KA, welding current is 3.5 KA, up time is 0.5ms, preheat current is 2ms, cool time is 0.5ms, welding time is 5ms, and electrode pressure is 20N. With the optimized processing parameters, the tensile-shear force of the welded joint can achieve 108.9N. The microstructures of welded joint that has best tensile-shear force are composed of swirling structure in weld nugget, uniform distribution of copper in weld nugget with a little of nickel.

Abstract: Prediction of the behavior of systems containing halogenated silanes required modification of the mixing rules used for solution models. In this work, interaction parameters for the characterization of binary systems of methylvinyldichlorosilane, methyltrichlorosilane, methyldichlorosilane and toluene at 101.3 kpa were evaluated accounting for the ideality of the vapor phase. The experimental measurements of liquid phase composition and bubble point temperature were found to be well represented by the Wilson model. Computed values of the vapor phase mole fractions, activity coefficients and excess Gibbs free energies from the model were presented and discussed.

Abstract: The single layer graphene oxide (GO) sheets-epoxy nanocomposites were prepared by directly dispersing concentrated GO aqueous colloid into dimethylformamide (DMF), and then incorporating the mixed solution into epoxy resin. The mechanical and thermal properties of the as-prepared nanocomposites were investigated by Notched Izod impact tests and thermogravimetric analysis. Significant improvements in both impact strength and thermal properties were observed for the nanocomposites at very low level of GO loading content. The impact strength of the nonacomposites containing 0.15 wt% GO was 10.66±0.75 MPa, which was 165.84 % higher than that of the pure epoxy resin (4.01±0.52 MPa). The decomposition temperature of the nanocomposites containing 0.3 wt % GO increased about 12 °C. The effective reinforcement of the GO based epoxy nanocomposites can be attributed to the good dispersion and the strong interfacial interactions between the GO sheets and the epoxy resin matrices.

Abstract: Recycled aggregate prepared from construction and demolition waste (C&DW) through sorting, crushing and screening process was mixed with an eco-cement (mainly from high calcium fly ash, granulated blast-furnace slag and clinker), antifreeze additives and water, forming high-performance load bearing brick. The product prepared conforms to GB/T21144-2007 (Concrete Solid Brick, China National Standards) with excellent freeze-thaw resistance and high strength. The effects of water-solid ratio and cementing material content on the performance of the product were investigated.

Abstract: Microstructure optical fiber materials has many virtues: small momofilament diameter, soft and flexible, high resolution, which make it have many broad application prospects in different fields, such as: high definition imaging equipment, industrial automation dectection, military and aerospace, etc. The materials of core, cladding and acid-soluble glasses were prepared, which had good physical and chemical matching on the base of three layers coaxial micro-structure. The double clad flexible fiber micostructure and spectral performances were tested. The experiments obtained high quality image transfer fiber, of which monofilament diametre is 10μm ± 0.1μm, resolution is 52.5LP/mm, transmittance is 42.6%/m. Experimental results showed that the preparation process broke through the traditional techniques and achieved the structure innovation, which had some reference value to improve the optical properties of image instruments.