Jorunal of Functional Materials

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Recent Advances in Preparation of Magneto-responsive Noble Metal Core-Shell Nanoparticles

rui-jing MA

Jorunal of Functional Materials. 2013, 44(14): 1975-1983.

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Abstract: Magneto-responsive core/shell-structured noble metal nanoparticles have potential applications in catalysis, optical, biosensors, and biomedical fields due to their unique property that is different from mono-metal nanoparticles. This paper reviews the recent progress in the synthesis and characterization of the magneto-responsive core/shell-structured noble metal nanoparticles according to their types. The applications of the core/shell-structured nanoparticles are also briefly intrduced.

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Structure performance and application research of natural Nano-tubular Chrysotile

Xi CAO;Chuan xiu yunHuang du bin

. 2013, 44(14): 1984-1989.

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As a unique natural silicate mineral fiber, chrysotile has many properties like nano hollow tubular structure, high surface chemical activity and biological activity. It is widely concerned and researched in the field of controlling environmental pollution、nanomaterials preparation. One-dimensional quantum dots and quantum wires can be prepared assembly by using chrysotile nanotubes as templates; The one-dimensional silica prepared after acid corrosion can also be used as carriers in synthetic one-dimensional nanocomposites, which will be widely used in catalytic, optoelectronics, and other aspects. It is very important to research on its nanotube and the physical and chemical properties, in order to utilize its uniform tubular structure, stable physical property, which has a very important practical significance for the development of natural nano-materials.

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State-of-arts of vacuum fabrication technology of CIGS thin film and its sputtering target

Leng Zhang

. 2013, 44(14): 1990-1994.

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Two vacuum preparing principles and procedures of CIGS thin film are illustrated in this paper. Relative merits of the two methods are investigated and analyzed. The molten casting method and powder metallurgy method for quaternary target manufacture are described. As required in the target preparation, the parameters, such as temperature, pressure and hold time, are elaborated. The annealed thin films which are sputtered from quaternary targets by employing uniform and fine powders, following with pressing and sintering, are supposed to have greater application prospects.

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Study on preparation and luminance properties of the single phosphor Tb3+ doped Ca2SiO3Cl2 for WLED

fang fang GUO

. 2013, 44(14): 1995-1997.

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Ca2SiO3Cl2:mTb3+ single white phosphors were synthesized by sol-gel at lower temperature studied. The phosphor shows some major emission peaks locating at 415、440、460、486、544、595、619 and 700nm by the near ultraviolet excitation which were mixed to white emitting. The blue emission increased firstly and then decreased with Tb3+ increased, whereas the green emission increased and the red emission decreased. When m=0.003, the chromaticity coordinates of the phosphor is x=0.317, y=0.3485, very closed to the standard white light (x=0.33, y=0.33), and it also shows middle-white emission (Tc=6161K). Ca2SiO3Cl2:Tb3+ is a kind of single phosphor with well white emitting properties used for WLED.

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Influence of CsCl on Structure and Properties of Ge23Se67Sb10 Infra-red Glass

. 2013, 44(14): 1998-2002.

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By using DSC, XRD, SEM, FTIR, Vickers and Archimedes method, the effect of CsCl addition on the characteristic temperature, the structure, the infrared transmittance, the micro-hardness and the density of Ge23Se67Sb10 glass have been studied. It is found that crystallites GeSe2 and Sb2Se3 precipitate in the glass matrix after CsCl is added into the glass. As the CsCl addition increases, the size of the crystallites increases . The characteristic temperature, the density and the infrared transmittance of the Ge23Se67Sb10 glass declines with increasing the CsCl addition. The micro-hardness of Ge23Se67Sb10 glass increases first and then decreases with the increase of CsCl addition. When the addition of CsCl is 2%, the micro-hardness of the sample reaches to 208MPa, which is higher than the base glass by 16%.

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Preparation and Property of Lanthanum Ferrite Formaldehyde Gas Sensor Modified by Carbon Nano Tubes and Silver

. 2013, 44(14): 2003-2005.

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The inorganic Perovskite compound is a kind of promising gas sensitive material due to its stable structure, and its cationic can be easily replaced by other ions. Silver-modified Lanthanum Ferrite (Ag-LaFeO3) has excellent gas sensitive characterization, but the operating temperature is still on the high side and the sensitivity is not ideal. This work based on the previous study of our research team. The Carbon Nano Tubes (CNTs) were used for further modification. CNTs-Ag-LaFeO3 powder was prepared by sol-gel method (sol-gel) combined with microwave chemical synthesis. The structure and gas-sensing properties were explored, the result shows: CNTs-Ag-LaFeO3 has an orthogonal perovskite structure. At 86℃, the sensitivity of 0.75%CNTs-Ag-LaFeO3 powder for 1 ppm formaldehyde is 13. The response and recovery time are 110s and 60s, respectively. 0.75%CNTs-Ag-LaFeO3 powder also has an obvious response for 1ppm formaldehyde at 58℃.

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Study on preparation and properties of super absorbent polymers thickening agent of thickening colloid

HUANG Yan-qin

. 2013, 44(14): 2006-2009.

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In order to obtain a stable thickening colloid, the high water absorption resin thickening agent was need. The super-absorbent polymer was prepared by the polymerization of aqueous solution. The copolymerization was carried out using acrylic acid and acrylamide as monomer, N,N-methylene bisacrylamide as crosslinking agent and potassium persulfate as initiator. The effects of monomer concentration, the degree of acrylic acid, initiator dosage and crosslinker dosage on water absorbency were investigated by orthogonal test. The super absorbent was obtained, its water absorbency was 3 114 g/g in distilled water and 157 g/g in 0.9% NaCl solution. It could be used as thickening agent to improve the thickening colloid practical performance.

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Preparation and photocatalytic properties of Ni-Zn ferrite nanopower

Yong-Gang ZHANG Hong-Zhi TANG

. 2013, 44(14): 2010-2013.

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Ni-Zn ferrite ( Ni0.5Zn0.5Fe2O4 ) photocatalyst were successfully synthesized using a sol-gel auto-combustion method at a low temperature of 200℃ which use nickel nitrate ferrite nitrate zinc nitrate as raw material ,citric acid and glucose as dispersant and combustion agent.The as-synthesized sample was analysed by XRD,TEM,VSM.The results show that the as-synthesized sample is a pure phase of spinel structure Ni-Zn ferrite and the particle size is about 18 nm,the saturation magnetic values(Ms) about 31.14emu/g with a remnant (Mr)2.08emu/g and a coercivity (Hc) of 62.17Oe showed ferromagnetic behavior.The photocatalytic activity of the as-synthesized sample was evaluated by the decomposition of methylene blue(MB) under Xe lamp irradiation.The results showed that in the Ni-Zn ferrite+H2O2+visible light system,the degradation rate of MB reach 98% in 2 hours.After reaction,the sample was recycled by magnetic force and washed by deionized water and absolute ethyl alcohol ,then,drying at 60℃.After 3 times repeatedly use found that the recycled catalyst show no reduce in the degradation rate.This suggesting that the sample is a promising ,stability ,recyclable photocatalyst.

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Study of the Electromagnetic Properties of the Low-Temperature Sintering Ferrite/Ceramic Composite Materials

Wei-Wei LING;

. 2013, 44(14): 2014-2017.

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Two kinds of ferrite/ceramic composite materials: MgCuZn ferrite/CaTiO3 (MCZF/CT) and MgCuZn ferrite/BaTiO3 (MCZF/BT) have been prepared at 900°C and 950°C by standard ceramic technology to adapt to the low temperature co-fired ceramic (LTCC) technology. It can be found that the cut-off frequency of each material increases from 13.9MHz (MCZF) to 136.9MHz (MCZF/CT), and the dielectric loss at 1MHz decreases from 0.741 (MCZF) to 0.012 (MCZF/BT). When the sintered temperature increases from 900°C to 950°C, the initial permeability, Snoek’s product and permittivity of two composites increase, and the dielectric loss decreases. Among them, the initial permeability of MCZF/CT reaches 51.8, which is obviously higher than that of MCZF/BT, but the latter has relatively better frequency characteristics in dielectric properties. Furthermore, the electromagnetic properties of the composites sintered at 950°C have been discussed combining with the analysis of microstructures.

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The effect of nano-Al2O3 particles to anodic oxidation on magnesium alloy

GOU Yin Ningyang hui;

. 2013, 44(14): 2018-2022.

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Abstract: Composite oxide films have been produced on AZ31 magnesium alloy by adding nano-Al2O3 particles to alkaline anodic oxidation solution. The effect of nano-Al2O3 particles on the process of anodizing, surface morphology and properties were analyzed by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Potentiodynamic polarization test and friction tests. The results show that the coating formation voltage increases with the addition of nano-Al2O3 particles. The performances of composite oxide films have no linear correlation with the concentration of nano-Al2O3 particles. The composite oxide film prepared in the presence of 10g/L nano-Al2O3 particles has uniform, smooth and compact surface morphology and shows best corrosion resistance and excellent wear resistance.

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Study on Low Temperature Sintered 0.4CaTiO3-0.6Ca(Mg1/3Nb2/3)O3 Dielectric Ceramics

Li ZHOU

. 2013, 44(14): 2023-2026.

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The dielectric ceramic of 0.4CaTiO3-0.6Ca(Mg1/3Nb2/3)O3 with glass of H3BO3-ZnO-R(BZR) as additive were investigated systematically.The results reveal that the BZR additive amount within a certain range(1m wt%～5m wt%,m is proportional coefficient and m>0) ,950 ℃ are the best sintering temperature ;sintered at 950 ℃,=47.26976,=0.0098 could be obtained for the 2m wt% BZR-added ; 3m wt% BZR additive also obtained optimal dielectric properties of =47.75029, =0.0102. And found that addition of BZR in modest amount can improve the crystal grain growth but too much addition may produce too much liquid phase in sintering process this would make liquid phase diffusion serious ,that could lead to some of the grain not fully growth and some abnormal growth with big size which resulted in the grain size uneven and then to influence the ceramic dielectric properties.

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Adsorption characteristics of the collagen fiber immobilized tannins for U6+

Han ZHOU;

. 2013, 44(14): 2027-2031.

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In this study, the adsorption performance of the collagen fiber immobilized tannins (CFIT) for removal U6+ in simulated radioactive waste water was investigated systematically. The effects of initial pH, adsorbent dosage, time, and initial concentration on the adsorption of U6+ was also studied. The results showed that CFIT possesses strong adsorption ability for U6+, which was mainly depended on the multi-molecular layer adsorption (chemisorption). Furthermore, a removal efficiency of 96.58% for U6+ was found when the pH and adsorption time was 5.5 and 4h, respectively. The thermodynamic parameter adsorption heat (ΔH=19.2942KJ?mol-1) was calculated and the positive value of ΔH showed the spontaneous nature of adsorption. The adsorption process was found to follow pseudo-second-order kinetics. The equilibrium adsorption data was well represented by the Langmuir adsorption isotherm equation and the saturated adsorption capacity for removal U6+ could reach a maximum of 352.1127mg ? g-1.

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Hot deformation behavior of Cu-Cr-Zr-Ce alloy at elevated temperature

;Bao-hong TIANYi Zhang

. 2013, 44(14): 2036-2040.

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Cu-Cr-Zr series copper alloys are usually used as lead frame materials for integrated circuit (IC) with high strength and high electrical conductivity. The flow stress change rules and deformation behavior of the Cu-Cr-Zr-Ce alloy during hot compression deformation were investigated with isothermal compression test method by a Gleeble-1500D thermal-mechanical simulator at elevated temperature. The true stress and true strain curves were measured at the test temperature ranging from 600℃ to 800℃ and the strain rate from 0.01s-1 to 5s-1. The microstructure evolutions of Cu-Cr-Zr-Ce alloy were analyzed with an optical microscope. The results show that the curves of true stress and true strain present characteristics of typical dynamic recovery. The flow stress and the peak flow stress increase with the decrease of deforming temperature and the increase of strain rate. The higher the deforming temperature and the less the strain rate, the easier the dynamic recovery and the dynamic recrystallization taking place. On the basis of the above experimental results, the hot deformation activation energy Q was derived from the correlativity of flow stress, strain rate and temperature, respectively. And the constitutive equation of the Cu-Cr-Zr-Ce alloy was also established, which indicates the relationship among the flow stress, the strain rate and the testing temperature during the isothermal compression plastic deformation.

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Study on principle of the shielding effectiveness of woven Fabrics Containing Stainless Steel Fibers and simulation

Zhou Ming

. 2013, 44(14): 2041-2046.

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According to the theory of electromagnetic shielding, principle of shielding effectiveness for textile containing metal fibers are briefly introduced. Based on this theory, a three-dimensional simulation model is established using the multi-physics coupled software COMSOL. Simulation test of several 304 austenitic stainless steel filament were done on different radius of stainless steel filament, different stainless filament distance, different polarization direction of EM wave and different radiation frequency. The result shows that fabric shielding effectiveness are effected significantly by different polarization direction, different radius and difference distance. These findings provide a theoretical proof in optimizing the designing of anti - electromagnetic radiation fabric made of metallic fiber fabric．

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Polyol-based synthesis of Fe3O4 nanoparticles and their microwave absorption properties

jing An;

. 2013, 44(14): 2047-2050.

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Fe3O4 nanoparticles were prepared by thermolysis of iron (Ⅲ) acetylacetonate in two different liquid polyols: poly(ethylene glycol) and tri(ethylene glycol). The nanoparticles are well dispersed, with the shape of approximately spherical and the average diameter of 7-8 nm. The results of X-ray diffraction and Transmission electron microscopy show that the particles have face-centered cubic structures and the stability of the aqueous suspension of Fe3O4 nanoparticles prepared in medium TEG is better than those prepared in PEG. Hysteresis loops of both samples show the superparamagnetic feature at room temperature, and give the magnetizations of 50 emu/g and 40 emu/g, respectively when external magnetic field reach 5 kOe. The microwave absorption measurement exhibited that the better dispersion of Fe3O4 nanoparticles can improve the reflection losses of samples.

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Preparation and Photoluminescent Properties of α-ZnS:Mn Nano-phosphor by Pyrolysis Method

. 2013, 44(14): 2051-2055.

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Sulfur metal-organic complexs were systhesized with Zn(NO3)2, Mn(NO3)2 and DDC(Diethyldithiocarbamate) as raw materials. ZnS:Mn nano phosphors were synthesized through pyrolysis sulfur meal-organic complex in different reaction solution at 200℃. The results show that high temperature phase α-ZnS:Mn with hexagonal structure was obtained. The ultraviolet absorption peak of the ZnS:Mn prepared in diethylene glycol adding 5ml oleic acid was the highest，the particle size was smaller. The maximum PL intensity is observed only at the excitation 323nm. Under the excitation of 323nm, a yellow-orange emission 585nm from the Mn2+ 4T1-6A1 transition is observed along with the blue emission 450nm. With the enhancement of Mn2+ ions concentration, emission intensity 585 nm increased firstly and then decreased. Emission intensity 585 nm was the strongest at 4.0% Mn2+. The correlation made through the concentration of Mn2+ versus PL intensity resulted in opposite trend of blue and yellow emissions.

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Electrodeposition and Characterization of Cu2O Thin Films

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. 2013, 44(14): 2056-2058.

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Cuprous oxide (Cu2O) films were fabricated by a two-pole electrodeposited method using indium-doped tin oxide (ITO) covered glass substrate and Cu strip. The influence of some technological factors (PH value, deposition potential) on Cu2O films was studied. The as-synthesized products have been systematically characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscope (XPS). The results indicate that the PH value and the applied potential play important roles in the Cu2O films. The optimum technological conditions are obtained as follows: the PH value is 5.7~5.9 and the applied potential is 1.1 V~1.3 V. What’s more, in this paper, we also put emphasize on the forming reasons of morphology of Cu2O.

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Stress corrosion behavior of Fe85Ga15 polycrystalline in simulated seawater

Jinxu LI;;;

. 2013, 44(14): 2059-2064.

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Effect of oxygen-carbon ratio on the homoepitaxial growth of diamond by microwave plasma CVD

Gao-Hua WU;

. 2013, 44(14): 2065-2068.

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Monocrystal homoepitaxial diamond has been grown on type Ib HPHT diamond (100) substrates using a 10kW, 2.45GHz stainless steel resonant cavity microwave plasma chemical vapor deposition (MPCVD) system with H2-CH4-CO2 as source gases. The effect of oxygen-carbon ratio on growth rate, morphology and crystallinity was investigated for the homoepitaxial diamond. The as-grown diamonds have been characterized using optical microscope, Raman spectroscopies and propeller micrometer. The results indicated that with the increasing of oxygen-carbon ratio, the diamond growth mode changes from two-dimension nucleation mode to step-flow mode and the the crystalline quality has been obviously improved while the growth rate substantially decreases. The optimized oxygen-carbon ratio was verified to be 0.8 for diamond homoepitaxial growth when microwave power is 7.8kW, methane-hydrogen ratio is 8％, gas pressure is 18 kPa and substrate temperatue is 1080℃, and the growth rate can reach 16μm/h. The addition of a proportional of CO2 into H2-CH4 gas phase system is an available way to improve crystallinity of the homoepitaxial diamond and to get relatively high growth rate.

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Preparation and Characterization of Co(Pd)CuZnLa/diatomite Catalysts by Modified Coprecipitation Method

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. 2013, 44(14): 2069-2073.

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Diatomite-supported Co-Ni-Cu-La and Pd-Ni-Cu-La composite metal catalytic materials were prepared by modified coprecipitation method of adding cationic surfactant CTAB. The prepared catalytic materials were characterized by some techniques of SEM, TEM, XRD, FT-IR, TPR and other tests in terms of their composition, surface area, morphology, reduction property. The results show that there are rich pores existed in the prepared catalytic materials, active oxide components of 4-15 nm have a good dispersion with flower distribution of 200-400 nm. Metallic simple substance and alloy can be obtained on the surfaces of the prepared catalytic materials by temperature-programmed reduced of hydrogen.

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Process parameters optimization for TiN/AlN multilayer films fabricated by pulsed laser deposition via SVR

Si-Jie HUANG;Cong-Zhong CAIQing-Wen ZENG

. 2013, 44(14): 2074-2078.

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Based on the experimental dataset of TiN/AlN multilayer films ablated on the monocrystalline silicon substrate via pulse laser deposition (PLD) technique, the support vector regression (SVR) combined with particle swarm optimization (PSO) is proposed to construct models for prediction the thickness of AlN thin films and hardness of TiN thin films in TiN/AlN multilayer films deposited under different process parameters. The predicted hardness of AlN films via established SVR model is compared with that obtained by immune radial basis function (IRBF) neural network using identical training and test samples. It is demonstrated that the mean absolute percentage errors achieved by SVR both for the training set and test set are smaller than those of IRBFNN, respectively. SVR possesses higher prediction accuracy and a better forecast capacity than IRBFNN. The established SVR model for TiN hardness was further employed to analysis and optimized the PLD deposition process, and was utilized to depict the interaction influences of multi-factor on the hardness of deposited TiN films. The method introduced in this study can provide scientific and theoretical guide in fabrication of TiN/AlN multilayer films via PLD, and it would be of important practical application value.

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Thaumasite Form Of Sulfate Attack On Different Variety Of Water Reducing Agent

. 2013, 44(14): 2079-2082.

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A thaumasite form of sulfate attack accelerated test was carried out to investigate the effect of different water reducing agents on thaumasite formation. Mortar samples were immerged in MgSO4 solution at 5% concentration. The appearance, strength and expansion ratio of corroded samples was observed. Besides, the corrosion products were also analyzed by X-ray diffraction, scanning electron microscope, energy dispersive spectrum, infrared spectrum methods and laser Raman spectrum analysis. The results show that the resistance to thaumasite sulfate attack (TSA) are different for the variety of water reducing agents. Polycarboxylate superplasticizer can’t resist TSA damage effectuall, but it exhibits a good resistance to the TSA.

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Preparation and performances of conductive functional aggregate containing super fine carbonyl iron powder

Yong-Jia He;;

. 2013, 44(14): 2083-2086.

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Conductive functional aggregate was prepared by mixing super fine carbonyl iron powder and clay powder together and calcining. XRD and SEM were used to investigate the mineral phases and microstructure of the aggregate. And the conductivity, porosity and water absorbing ratio of the aggregate, and its effect on conductive performance of carbon fiber reinforced concrete were studied. Results showed that super fine carbonyl iron powder can exist in ceramic matrix and act as conductive phase, and tunnel transition of electron can occur among the micro particles and forms electric current. In this experiment, 6.5 vol% content of iron powder is the percolation threshold for forming the conductive network. Content of iron powder has effect on porosity and water absorbing ratio of the aggregate by affecting the formation of liquid phase in the calcination process. Compared to common non-conductive aggregate, conductive aggregate obviously decreased the resistivity of concrete at the same carbon fiber content.

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Controlled Fabrication of Ordered Macroporous TiO2 Bilayer Films for the photoanode in Dye-Sensitized Solar Cells

. 2013, 44(14): 2087-2091.

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Hierarchically ordered macroporous TiO2 bilayer films which were prepared by PS colloidal crystal templates method, were applied as the photoanode in the dye-sensitized solar cells (DSSCs). The microstructure of the as-synthesized products were characterized by scanning electron microscope (SEM), X-ray diffractometer (XRD), high resolution transmission electron microscope (HRTEM) and nitrogen adsorption-desorption analyzer. The results showed that the macroporous TiO2 films replicated well the three-dimensionally ordered structure derived from PS colloidal crystal templates and revealed a relatively large specific surface area. The photoelectric test results indicated that the photovoltaic conversion efficiency was improved from 4.16% to 6.08%, as compared to a device using a pure P25 TiO2 photoanode. Our results showed that the hierarchically ordered macroporous TiO2 bilayer films photoanode had important and potential applications in DSSCs.

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DeNOx performance of quaternary SCR V2O5-WO3-MoO3/TiO2 catalyst

Yan GAO;Tao LuanJiwei Peng;Tao Lv

. 2013, 44(14): 2092-2096.

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The quaternary SCR catalyst was prepared with anatase TiO2 as the support, V2O5 as the main active agent, WO3 and MoO3 as the active coagent. The deNOx efficiency, catalytic selectivity, thermo stability and microscopic characterization of this catalyst were studied. The results showed that the deNOx efficiency of this quaternary catalyst was higher than the ternary catalyst singly loading W or Mo at the same weight percent. W improved the deNOx efficiency at high temperature and inhibited the side reaction caused by Mo at the temperature above 400 °C, while Mo improved the deNOx efficiency at low temperature which made up for the lower deNOx efficiency of W at the temperature below 300 °C. The maximum deNOx efficiency of this quaternary catalyst was 99%, the temperature window (deNOx efficiency>80%) was 280~420 °C, and the SO2 oxidation in the range of 180~380 °C was zero. There were three weight loss peaks for the quaternary catalyst in the range of 0~1000 °C, crystal water evaporation at 100~130 °C, organic additive decomposition at 230~270 °C and inorganic salt decomposition at 500~530 °C. The microscopic characterization showed the particle of this catalyst was uniform and compact, the grain size was consistent with no apparent agglomeration and macro pore structure was complete.

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Experimental Research and Numerical Simulation on Static Deformation of Gasbag with Textile Reinforced Composite Lining

Shuai WANG

. 2013, 44(14): 2097-2100.

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In order to study the static deformation process of gasbag with textile reinforced composite lining, this paper designed an experiment platform according to the performance of this kind of gasbag. Firstly, loaded high pressure gas into gasbag, then researched on the deformation process of gasbag. Secondly, used LS-DYNA software, for finite element analysis, to build model for gasbag inflation, then did numerial simulation for the whole inflation process. According to the experiment result, analyse the change of inflation transformation and the deformation law of the gasbag, and get time-dependent changes of height, volume and pressure of the inflated gasbag. Experiment data is basically consistent with the result of numerial simulation.

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Isothermal Adsorption of Alkylammonium in Middle Charged Montmorillonite

QIU JUN;;

. 2013, 44(14): 2106-2110.

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Montmorillonite/Alkyl ammonium compound is a mineral composites with high added value, the adsorption amount is closely related to the gel performance of the composite .In this paper, On base of purification and sodium modification of the lower charged bentonite from Shandong Province, at 80℃，adsorption characteristics of Octadecyl trimethyl ammonium (OTAC), Cetyl trimethylammonium (CTAC) and Tetradecyl trimethyl ammonium (TTAC) in montmorillonite are systematically researched. The research results are as the following: At a higher dosage in the organic system , all the three alkylamines exhibit excessive adsorption characteristics in montmorillonite interlayers, the saturated adsorption amount increases with he length of the carbon chain in the Alkylammonium. The isothermal adsorption of the three alkylamines are fitted well with Modified Langmuir models，the fitting degree of the three alkylamines are respectively 0.992、0.986和0.977. Correspondingly the saturated extent of adsorption of OTAC, CTAC and TTAC are 2.101 mmol/g,2.042 mmol/g, 1.760 mmol/g, which fit well with the experimental data .

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Characterized and prepared a new type of PEG derived hydrogelunder mild condition

. 2013, 44(14): 2111-2114.

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PEG derived hydrogels were synthesized by a novel synthesis route unde rmild condition. First, we synthesized a soluble linear copolymer by amino-terminated polyethylene glycol ATPEG and Pyromellitic dianhydride (PMDA), named by p (ATPEG-co-PMDA). The copolymer with imide rings on the main chain can be soluble in most of solvents. Then, the imide-rings of the copolymer were open by amino groups of Butanediamine (BDA) under ambient condition to form cross-linking network. The cross-linking network can form in few minutes. The p(ATPEG-co-PMDA) and gels were characterized by 13 C NMR and FTIR. The gels swelled significantly in water, and co-continuous porous structure was observed by scanning electron microscopy. The ring-opening cross-linked reaction of p(ATPEG-co-PMDA) provided a simple, versatile approach to hydrogel network under mild condition without initiator, which have potential as biomaterials to apply in biomedical region.

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Improvement of thermal stability of nanometer SnO2 by surface chemical modification with SiO2

. 2013, 44(14): 2120-2123.

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The ethoxyl groups of 3-aminopropyl triethoxysilane (3-APTES), as a surface modifier, reacted with hydroxyls of SnO2. SiO2 was grafted on the surface of SnO2 to inhibit the growth of the SnO2 nanocrystal. As-synthesized samples were characterized by SEM, TEM, FT-IR, XRD and EDS. The results show that the SiO2 remains strongly bonded at the SnO2 surface through Sn-O-Si bonds, the average particle size of modified SnO2 is only 10nm after 1000℃ calcination. However, that of pure SnO2 is 95nm at the same calcination. The well-dispersed SiO2 as a second phase resists the movement of grain boundary and increased the activation energy of crystal growth. Nanocrystal growth of SnO2 is effectively restricted up to 1000℃. So the thermal stability of SnO2 has been improved.

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Synthesis of Fluorescent Hydrotalcite/PMMA Nanocomposite by Microwave Implosion Method

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. 2013, 44(14): 2124-2127.

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An exfoliated yellow light emission polymer/layered inorganic nanocomposite was rapidly synthesized by microwave implosion method. The composition and structure of the resulted nanocomposite were characterized and determined by fluorescence spectrum, XRD, TG, TEM, etc. The results indicate that the brucite-like layers of hydrotalcite-like compound were completely exfoliated in PMMA matrix, the nanocomposite can mainly emit yellow light under excitation at 468nm. The nanocomposite also has better thermal stability than that of the pure PMMA. Microwave implosion method provides a new and efficient way in which the inorganic layers can be exfoliated rapidly and uniformly disperse in the polymer matrix in nano-sized. The method is expected to be applied in the synthesis of various types of polymer/layered inorganic nanocomposites.

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Model of effective thermal conductivity of nanofluids based on small scale effect of nanoparticles

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. 2013, 44(14): 2128-2131.

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By analyzing the heat transfer mechanism of nanofluids based on the small scale effects of nanoparticles, a predictive model of the effective thermal conductivity of nanofluids was developed. By comparing with experimental data and the classical models, it was found that at room temperature both the proposed model and the classical models exhibited good performance in predicting the thermal conductivity of nanofluids, but at higher temperatures the prediction values of the proposed model fit the experimental values better, indicating that it is more applicable for calculating the thermal conductivity of nanofluids at different temperatures. On this basis, the influence of temperature, volumetric concentration and particle size of nanoparticles on the nanofluid thermal conductivity was discussed, together with the contribution of both the nanoparticles and the base fluid to the thermal conductivity enhancement of nanofluids at different temperatures.

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30 July 2013, Volume 44 Issue 14