30 November 2015, Volume 46 Issue 22
    

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  • Preparation and properties of functional coating with diatomite loading titanium
    Wei Li
    . 2015, 46(22): 1-0.
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    Abstract: With the increasing requirements on the quality of life and interior decoration materials, functional coating attracts more and more attention. A kind of functional coating was prepared by traditional coating technology using diatomite as the base material. Titanium was loaded on the diatomite through the homogeneous hydrolysis method of titanic chloride. Results showed that the titanium loading on the diatomite was high and stable. The optimum loading condition was as follows, the theoretical content of loaded titanium was 100%, temperature was 80℃, concentration of urea was 0.2mol/L, reaction time was 1h. Under this condition the content of actual loaded TiO2 reached up to 74.7% and the minimal inhibitory concentration of the diatomite loading titanium was 8g/L as the rate of antibacterial efficiency up to 99.7%. The moisture absorption of the functional coating prepared by the diatomite loading titanium was 12%; the diameter of antibacterial circle was 4mm. It indicated that the functional coating with diatomite loading titanium had good moisture absorption and antibacterial performance which suggesting it would be a kind of promoting coating.
  • Preparation and characterization performance of dimethylallyl quaternary ammonium salts of lignin - sodium alginate polyampholyte
    Qiong ZHANG
    . 2015, 46(22): 2-0.
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    In order to improve application of lignin, dimethylaiiyl quaternary ammonium salt of lignin-sodium alginate polyampholyte (DL-SA) was prepared with dimethylallyl quaternary ammonium salt of lignin (DL) and sodium alginate (SA) and the cross linker was glutaraldehyde. The optimum conditions obtained by monotheism experiments were on the standard of nitrogen content and flocculate ability for acid black ATT, which include: m(DL):m(SA)=2:1; 75℃ of reaction temperature, 4h of reaction time and 4 wt% of the glutaraldehyde dosage, which the decolorization rate of acid black ATT was 90.08%. It was investigated the solubility and amphoteric polymer characteristics, ie, isoelectric point. Its structure was analyzed by FTIR, which was found that DL and SA was grafted successfully, and its nitrogen content was reduced from 2.14% to 1.25%. Its isoelectric point was 4.22 and it has compound characteristics.
  • Influence on surface characteristics of micro-arc oxidation ceramic coating by H2O2 on casting aluminium alloy
    Kai Lü LIU Xiang-dong
    . 2015, 46(22): 3-0.
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    The ceramic coatings were obtained on casting aluminum alloy surface in Na2SiO3 electrolyte system containing H2O2 by micro-arc oxidation. Microstructure and roughness analyses in combination with microscopic examinations have been performed in detail through atomic force microscope (AFM) and scanning electric microscopy (SEM). Characteristics of the coating such as thickness and phase composition which were influenced by H2O2 were investigated. The results showed that with increasing the H2O2 concentration in the Na2SiO3 electrolyte, the thickness decreased, the compactness and Al2O3 increased. It is found by AFM and SEM that the coating surface quality was improved and the roughness was decreased which were due to addition of H2O2.
  • Progress on the quantum dots growth mechanism simulated by Kinetic Monte Carlo
    Yu YANG
    . 2015, 46(22): 4-0.
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    To understand the factors which effects the formation of quantum dots (QDs), the kinetic Carlo (KMC) method has been extensively used to simulate QD growth. In this paper, the advantage and the progress of KMC method have been well introduced. Based on the model structure and the interaction potential between atoms, we discussed the QD growth process including the transition from 2 D to 3D growth, the nucleation site, the QD size distribution, and the morphology evolution respectively. Moreover, the calculation progress on the ordered QDs grown on the patterned substrate is also concluded. Our review may give some beneficial guidance for the nanomaterial growth and the consequent device fabrication.
  • Preparation and Fluorescence Emission Characteristics of Polymer-Rare Earth Complexes Formed by Polystyrene with Bidentate Schiff Base Ligand-Containing Side Chain and Eu(Ⅲ) ion
    Ming BaoGAO
    . 2015, 46(22): 5-0.
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    Abstract: Bidentate Schiff base (SB) ligand was bonded on the side of polystyrene (PS) by molecular design and via several steps of polymer reactions, and the bidentate Schiff base ligand-functionalized PS, PS-SB, was obtained. PS-SB was used as macromolecular ligand, and the coordination reaction between it and Eu(Ⅲ) ion was allowed to be carried out, resulting in the binary polymer-rare earth complex PS-(SB)3-Eu(Ⅲ). At the same time, with phenanthroline as second ligand, the ternary polymer-rare earth complex PS-(SB)3-Eu(Ⅲ)-(Phen)1 was also prepared. On this basis of characterizing the two complexes by infrared spectroscopy and ultraviolet absorption spectrum, their fluorescence emission characteristics and luminescent mechanism were examined in depth. The experimental results show that the bond bidentate Schiff base ligand SB possesses the dual functions of coordination chelating and energy transfer-sensitization towards rare earth ion. Therefore, the prepared complexes are stable, and can emit strong characteristic fluorescence of Eu(Ⅲ) ion. The macromolecular ligand PS-SB itself has strong fluorescence emission. However, after coordinating with Eu(Ⅲ) ion, the fluorescence emission of its own weakens remarkably, and the energy is transferred to Eu(Ⅲ) ion via intramolecular energy transfer. As a result, Eu(Ⅲ) ion fluorescence is strongly sensitized. The fluorescence emission intensity of the ternary polymer-rare earth complex PS-(SB)3-Eu(Ⅲ)-(Phen)1 is much higher than that of the binary polymer-rare earth complex PS-(SB)3-Eu(Ⅲ) owing to the two effects of the second ligand Phen, synergistic coordination and replacement of coordinated water molecules.
  • Synthesis of SiO2 nanoparticles in the reverse microemulsion and fabrication and characterization of the resulting hybrid membranes
    Li-Guang Wu
    . 2015, 46(22): 6-0.
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    SiO2 nanoparticles were firstly synthesized in a reverse microemulsion using triblock copolymer PEO-PPO-PEO (F127) as the surfactant, methyl methacrylate (MMA) as the oil phase, and NH3?H2O solution as the hydrolysis catalyst, after TEOS was added to the microemulsion as the precursor of SiO2. Then, SiO2/PMMA inorganic-organic hybrid membranes were successfully fabricated by in-situ microemulsion polymerization. The formation and the morphology of SiO2 nanoparticles in reverse microemulsion were analyzed via UV-Vis absorption spectroscopy and Transmission Electron Microscopy. The effect of SiO2 nanoparticles on the polymerization of MMA was explored by measuring the change in the viscosity of solution during polymerization. Scanning electron microscopy was employed to characterize the morphology and surface properties of hybrid membranes. The separation performance of these novel hybrid membranes was evaluated by gas permeation experiments. The results showed that more SiO2 nanoparticles with small size generated in the reverse microemulsion. Due to the protection of surfactant on the particles during the polymerization, SiO2 nanoparticles distributed homogeneously in the membranes, which improved significantly the performance of hybrid membranes for CO2 separation. Both the gas permeability and separation performance of the hybrid membranes first increased and then decreased with SiO2 content. When the TEOS was 4.0 mL, the CO2 permeability of hybrid membrane is 1.64×105 barrer, CO2/N2 permeation selectivity can reach 27.31.
  • Primary investigation on mechanical reproducibility of titanium foams
    Jian Xiao
    . 2015, 46(22): 7-0.
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    Repetitive manufacturing is the important premise of a novel material with a large-scale commercial applications. Titanium foam served as a novel metal foam has been obtained a attractive application prospect in fields of biomedical bone substitutes and catalyst carrier in battery. In this article, the mechanical reproducibility of titanium foams prepared by the well-established space holder technique was initially investigated. The results show that the porosity was reproducible while the reproducibility of mechanical properties as Young’s modulus and compressive strength of titanium foams were poor. It was found that the poor reproducibility of mechanical properties is mostly attributed to the uncontrollable factors as the microstructure and cell-walls defects obtained from the preparation process. From the point of view of process, it is a feasible path to improve the mechanical reproducibility of titanium foams through increasing the content or decreasing the size of the spacer holder material.
  • Research of wetting and drying of the hydrophobic membrane pore
    lu xiaolong
    . 2015, 46(22): 8-0.
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    Abstract: For the problem that the drying of the hydrophobic membrane pore, we proposed a new method of drying the membrane pore that there is a critical wetting depth and automatic dehydration effect for hydrophobic membrane. When the wetting depth of membrane pore is less than the critical wetting depth, the membrane can realize automatic dehydration under the effect of surface tension. In this paper, sodium dodecyl benzene sulfonate solution was used as quickly pollutants, The polyvinylidene fluoride (PVDF) hollow fiber hydrophobic membrane was applied in vacuum membrane distillation (VMD) process for the research of the membrane pore wetting and dehydration drying. The results showed that, for the three membranes with different thickness, there is a critical wetting depth for hydrophobic membrane, its values are 19.5±0.5μm, the depth was not associated with the thickness of the membrane. Clean the membrane when the wetting depth was less than the critical wetting of the hydrophobic membrane, the hydrophobic membrane’s automatic dehydration drying can be achieved, enabling continuous operation of membrane distillation process.
  • The antifriction and antiwear properties of the surface micro-stripe texture Ti6Al4V under different friction direction
    Wengang CHEN
    . 2015, 46(22): 9-0.
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    The titanium alloy surface was texturing treated by laser processing equipment. The isometric grid with spacing of 100μm was obtained. The friction and wear experiments were conducted by using the MRTR multi-functional friction and wear tester in oil bath condition. The sliding angle of the friction pair and textured surface is 0°, 45°and 90°, respectively. The worn surface was detected by using SEM. The experimental results show that the friction coefficient of the textured surface are about half of the smooth surface in the steady state at every different sliding angles. The friction properties of the textured surface when the friction angle are 45°and 90°were better than friction angle is 0°. Especially the friction angle of 90°.
  • The simulation and research with deformation behavior and mechanical properties of stents in narrow blood vessel
    Hai-Quan FENG
    . 2015, 46(22): 10-0.
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    Rate of stenosis reflects the level of vascular stenosis, different stenosis rate do different impact on mechanical properties of vascular stents. Going simulation and analysis using finite element method on four different stents under the stenosed rate of 30%, 40%, 50%, investigate the effect of stenosis rate on stents’ deformation behavior and mechanical properties. Result shows:There is little effect on equivalent stress of stents which generated from stenosis rate,but the stents’ structure exert an significant effect on stress distribution of blood vessels,the effect on vascular stress which open loop stents supported is obvious than the one closed loop stents supported; With the increase of stenosed rate, the axial shortening rate of stents have a tendency to decrease, radial spring-back rate and expansion uniformity have a tendency to increase, vascular stress have a tendency to increase too;the impact on closed loop stents' radial spring-back rate and expansion uniformity caused by stenosed rate is obvious than the one on open loop stents. By analyzing the influence caused by stenosed rate, showed the impact on different stents caused by different serious of blocked arteries, provided theoretical basis for designing and implanting of the stent.
  • Preparation of g-C3N4 and Photocatalytic Performance under Visible Light Irradiation
    hong-yan LIU
    . 2015, 46(22): 11-0.
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    Make the urea and melamine with the mass ratio of 6:4 mixed, and then take in the muffle to calcine, received the g-C3N4. The structure of g-C3N4 were analyzed by XRD、TEM、BET、FT-IR、UV-vis、PL. The results shows, when the calcination temperature is 520℃ , the urea content reaches 60%, the g-C3N4 be exist with the layer structure, and the surface areas is 40.63 m2/g. Be accompanied the illuminate of LED with 12W, after 2 hours the MB with 15mg/l were degraded 92.1% by the sample.
  • Preparation, Characterization of Dawson type aluminium phosphotungstate and its Catalytic Performance in synthesis of Butylparaben
    Xiao-Hua CAO
    . 2015, 46(22): 12-0.
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    Dawson type aluminium phosphotungstate was prepared by the precipitation method, and characterized by FT-IR, SEM, EDS, Py-IR and NH3-TPD. Then it was used in the preparation of butylparaben as catalyst for the first time. Results of Py-IR reveal that A1H3P2W18O62 has both Br?nsted and Lewis acid centers. NH3-TPD results show that A1H3P2W18O62 has weakly acidic sites, strong acid sites and super acid sites, the major part of acid sites were strong acid site. The optimum esterification conditions determined by orthogonal experiments were: mass ratio of catalyst to reactants, 4.9%; molar ratio of n-butyl alcohol to p-hydroxyl benzoic acid, 3:1; the reaction temperature, 120℃; the reaction time, 3.0 h. Under these conditions, the yield of butylparaben was up to 93.2%, which is higher than those with Dawson type phosphotungstic acid or concentrated sulfuric acid as the catalyst. A1H3P2W18O62 can be easily recycled and reused, the yield of butylparaben remains up to 73.1% after 5 cycles.
  • Preparation and Properties of Titanium-contained SiliconeHybrid Films with High Refractive Index
    Ya-Wen LAI
    . 2015, 46(22): 13-0.
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    Tetrabutyl titanate (TBOT) and diphenyldimethoxysilane (DPS) were used to condensate with two kinds of silanes with different alkyl chain lengthhexyltrimethoxysilane (C6TMS) and n-Dodecyltrimethoxysilane (C12TMS), respectively. Two kinds of titanium-contained siliconehybrid sols seriesBTS and CTS were synthesized. The effects of Ti content and alkyl chain length on thermal stability against yellowing, refractive indexand transmittance of the films were studied. The results indicated that transmittance in visible range of all films was above 98%; refractive indices of the films BTS series and CTS series were tunable between 1.5584~1.6137 and 1.5721~1.6515, respectively. TGA and thermal aging test indicated that the thermal stability against yellowing of the hybrid films increased with long alkyl chain length and more Ti content. The mechanism of yellowing of Ti-contained materials was also discussed.
  • Synthesis of Lead-Free Flux Coated Ce2S3 Red Ceramic Pigments
    Zhen-Feng ZHU Hui Liu
    . 2015, 46(22): 14-0.
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    Lead-free flux coated Ce2S3 red ceramic pigments were prepared by a conventional solid-state route. The impact of cerium flux mass ratio and cooling method on the coloring properties and thermal stability were investigated. The result shows that the coating property of samples is best when the cerium flux mass ratio is 1:1, and taking out directly into water. In this case, dense protecting coating layers of lead-free flux form on the surface of the pigments. The sintered samples have high crystallinity and hues with Ce2S3 successfully encapsulated by lead-free flux, which have potential to be used as ecological red pigments for ceramic applications.
  • Study on MgO modified asbestos paper separator for thermal batteries
    . 2015, 46(22): 15-0.
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    MgO modified asbestos paper was prepared by high temperature decomposition of magnesium acetate precursor and used as separator for thermal battery. A sing cell was fabricated with a NiCl2 film cathode, the modified asbestos paper loaded with an eutectic moten electrolyte LiCl-LiBr-KBr and a LiB anode. The influences of the loadings of MgO and electrolyte in the separator and operating temperature on the discharge performances of the single cells were studied. The results indicates that the single cell employing the separator with a MgO loading of 5.2mg/cm2 and an electrolyte loading of 53mg/cm2 shows the best discharge performance. And at current densities of 50, 100 and 200mA/cm2, the respective cell voltage can reach 2.4557, 2.4375 and 2.3285V. The performance is comparable with that of the cell using the cold pressed electrolyte pellet. A thermal battery prototype with 5 single cells is fabricated and at a discharge current density of 100mA/cm2, the obtained voltage rise-time is 0.26s and working time is 110.0s with a cut-off voltage of its 80% peak voltage.
  • The Influence of Ce Concentration on The Structure and Performance of TiAl Intermetallic Compounds
    . 2015, 46(22): 16-0.
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    Basing on the first principle calculation of density functional theory, electronic structure, elasticity and electronic properties of different concentrations of Ce doping with TiAl are calculated. The calculation results show that：as TiAl has been doped with Ce, internal orbital hybridization of TiAl is enhanced, covalency, bonding direction and hardness are improved. The ionic bond is formed between Ce, Ti and Al atoms, ionicity is enhanced and ductility is increased. As the doping concentration of Ce has been improved, ductility and hardness of TiAl are increased.
  • Study on the interfacial bonding performance of foam concrete sandwich wallboard
    . 2015, 46(22): 17-0.
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    In this paper, composite board was prepared by pouring foam concrete, and the bonding strength between foam concrete and calcium silicate board was discussed. The influence of processing methods of calcium silicate board and admixture of foam concrete on the bonding strength of the composite board were investigated. The results show that the bonding strength of composite board increased when the dosage of emulsion powder increased. The bonding strength order with different processing methods of calcium silicate board was dry+glue+groove＞dry+glue＞dry＞wet. When the relative moisture content of calcium silicate board was between 0% and 50%, the bonding strength was higher than 200kPa. Thickening agents can improve the stability of fresh foam concrete in composite board, without adverse effect on the bonding strength. Accelerator would decrease the bonding strength. In consideration of bonding strength, stability of foam concrete, and cost of production, by using foam concrete with 1% of emulsion powder and a few thickening agent, and using composite board with 50% relative moisture content, composite board with high bonding strength and non-collapse can be prepared.
  • Effect of ligament structure on the elastic wave propagation band gap in chiral metamaterials
    Ji-Long Su
    . 2015, 46(22): 18-0.
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    A hexagonal chiral cellular metamaterials was taken for example, the focus was put on investigating that the effect of dynamic characteristics of material microstructure ligaments on band gap characteristics of elastic wave propagation in such chiral metamaterials. Firstly, a calculative model of natural frequencies for ligaments was established based on considering the elastic supports existing between the ligament and the node. Then, the formation mechanism of elastic wave propagation band gap existing in chiral periodic structure metamaterials was explored. The results show that, compared with the fixed support, the vibration frequency is lower when the ligament is elastic supported, and ligament is shorter, it is more sensitive to the elastic support. The formation mechanism of elastic wave propagation band gap is that the vibration is localized to a small number of ligaments. The results imply that we can achieve versatile control band gap structure by adjusting connect elasticity of ligaments and their mass distribution.
  • Preparation and Properties of BNKLT Lead-Free Piezoelectric Ceramics
    . 2015, 46(22): 19-0.
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    Tianjin University of Technology, Tianjin 300384，China) Abstract: Bi0.5(Na0.8K0.2-xLix)0.5TiO3 lead-free piezoelectric ceramics were prepared by solid state reaction method. The effect of composition and sintering process on the phase, microstructure and electric-properties were studied. The results show that the average grain sizes of the mixed power are about 2μm. The calcination temperature of 900℃ is determined by thermal analysis. By XRD detecting, the calcinated powder are ABO3 perovskite structures and all ferroelectric tetragonal phase. By SEM, the good sintering ceramics with a high density are obtained for the ceramic with x=0.06 and sintering temperature of 1160 ℃.The excellent electric properties of εT33/ε0=1160, tanδ=0.029, d33=160 pC/N, kp=0.407 are tested at the composition.
  • Analysis on Conductive Mechanism of Magnetorheological Elastomers
    Xu-Li ZHU
    . 2015, 46(22): 20-0.
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    The particles inside a magnetorheological elastomer (MRE) align themselves to lines along the direction of magnetic field during fabrication of the MRE. MREs can be conductive because the particle lines act as conducting channel. The conductive unit was constructed as the conducting units according to the characteristic of particle structure inside MREs. The conductive property of the conducting units was analyzed and then the analytical expression for electrical conductivity of MREs was derived. An MRE was fabricated and the conductive property of it was tested, and the expression was verified. The results show that the current flowing through an MRE includes conduction current and tunnel current, and the electrical conductivity of an MRE is a nonlinear function depended on voltage acted on it.
  • Study on the influent factors of magnesium phosphate cement hydration heat
    Jian-Hua DING
    . 2015, 46(22): 21-0.
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    Micro calorimeter of eight channels is used to study the influent law of different M/P ratio (quality ratio of magnesium and potassium dihydrogen phosphate), the ratio of water and binder (W/B ratio), borax content, dosage of fly ash and phosphate species on the magnesium phosphate cement hydration heat. The results show that the magnesium phosphate cement hydration is an endothermic and exothermic process. It has one endothermic valley and two exothermic peaks. The endothermic valley arises from the dissolution of phosphate, the exothermic peaks associate with the dissolution of magnesia in acid solution and the formation of product. The release rate of heat and heat quantity of magnesium phosphate cement hydration is reduced by improving the M/P ratio, the W/B ratio, borax content and dosage of fly ash. The hydration exothermic peak and heat of magnesium phosphate cement of ammonium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate is 0.430714 W, 0.145677 W, 0.194626 W and 1198.949 J, 452.798 J, 902.872 J, respectively, which not only indicates that phosphate species have significant influence on hydration heat, but also is related to their the solubility and pH value.
  • Tetragonality and Size Control of Barium Titanate Nanopowders Prepared by Solvothermal Method
    . 2015, 46(22): 22-0.
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    Tetragonal BaTiO3 nanopowders have been prepared by solvothermal method , the tetragonality, particle size and distribution of as-prepared BaTiO3 particles were optimized by adjusting soaking time and molar ratio of precursors(Ba/Ti(mol)), The characterization of specific surface area, laser particle size, SEM, XRD and FT-IR indicated that prolonging soaking time could reduce the content of –OH, leading to enhance the tetragonality of as-prepared BaTiO3 nanopowders, meanwhile the particle size and distribution became larger. With Ba/Ti(mol) increasing, the particle size first increased and then decreased, correspondingly the content of –OH became lower, but because of size effect the tetragonality did not present a tendency of linear increase due to less content of –OH. The BaTiO3 nanopowders synthesized in the condition of 1h soaking time and Ba/Ti(mol) = 2.5 is suitable for preparing MLCC consisted of less than 2μm ceramic tape due to small particle size, narrow distribution and high tetragonality.
  • Study of conductivity optimization and electro-active response of ion-exchange polymer
    Shao-Ming Fang
    . 2015, 46(22): 23-0.
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    In this paper, we firstly prepared graphene monolayer carrying Ag nano particles (GO/Ag NPs); then, widely dispersed GO/Ag NPs into the commercial the Nafion solution, thus obtained the GO/Ag NPs hybrid ion-exchange membrane; finally, sandwiched the ion-exchange membrane by two layers of Pt nanosheets, thus obtained hybrid ion-exchange polymer metal composite (IPMC) actuator. Detections of electrochemical impedance spectroscopy (EIS) and electromechanical properties of IPMC show that, after hybrid of GO/Ag NPs, conductivity of the ion-exchange membrane increases, both the swing angle and force output increase; electromechanical properties of IPMC has a close relationship with the conductivity, which can act as a valuable parameter to evaluate the electromechanical properties.
  • The structure and passivation effect for the c-Si wafer of a-Si:H films with different processing parameters by HWCVD
    Yu-ping He
    . 2015, 46(22): 24-0.
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    Bifacial-deposited a-Si:H films were made on n-Cz-Si with different processing parameters by HWCVD, the structure and the passivation effect of a-Si:H films were analyzed by spectroscopic ellipsometry(SE) and Fourier Transform Infrared Spectroscopy(FTIR) with different depositing pressure, current, and distance between filament and substrate. The results show that: (1) Relative content of SiH2 to SiH bond in films decreases with the pressure increasing, but decreases firstly then increases with current increasing. (2) Compare to 7.5 cm of distance between filament and substrate, the samples of 4.0 cm, proportion of the SiH2 bond compare to SiH bond is higher, passivation effect is better. (3) Within the scope of this study, the passivation effect is optimal with pressure 1.5Pa, current 21.5A, distance 7.5cm, surface recombination velocity 2.9cm/s.
  • Biosorption of Pb(II) and Cr(III) from aqueous solutions by carboxyl-functionalized durian shell
    Wen-Bing WU
    . 2015, 46(22): 25-0.
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    The adsorption efficiency, isothermal adsorption and kinetics of durian shell modified by citric acid for Pb(II) and Cr(III) from aqueous solution was investigated. Both modified and unmodified adsorbents were characterized by FTIR, SEM and XPS, and modification and adsorption mechanism of durian shell was discussed. The results of FTIR and XPS demonstrated that after modified by citric acid via N,N'-carbonyldiimidazole as a activator, the new peaks at 1730 cm-1 and 1640 cm-1 were assigned to ester carbonyl groups and carboxylate stretching band on durian shell and the O/C atom mass ratio increased, which indicated the presence of citric acid grafted onto durian shell. Adsorption results showed that, the adsorption capacity of durian shell modified by citric acid for Pb(II) and Cr(III) were 3.15 and 2.42 times as those of the natural durian shell, respectively. The adsorption of Pb(II) on durian shell modified by citric acid exhibited a stronger competitive effect than Cr(III) in the aqueous solution with two coexisting anions. The adsorption kinetics data showed that the adsorption equibrium was reached in 120 min for Pb(II) and Cr(III) and the data of adsorption rate could be described by pseudo-second-order rate model (R2>0.9975). At 25 degrees Celsius, the isothermal adsorption of Pb(II) and Cr(III) on durian shell modified by citric acid tended to be fitted well by the Freundlich model (R2>0.9902). Adsorption-desorption results showed that the CM-CDI-DRS remained high biosorption ability for Pb(II) after four-time usage.
  • Preparation and Electrochemical Properties of CNTs/Polyimide composites
    Bao-Ming LI
    . 2015, 46(22): 26-0.
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    The CNTs/PI composites were prepared by in-situ polymerization from DCP, BTDA and CNTs as raw materials and their molecular structures, crystallinity, microstructure and electrochemical properties were studied. The results showed that CNTs/PI composites were partially crystalline materials, and CNTs were coated by PI uniformly. CNTs/PI composites had better electrochemical redox behaviors and the oxidation potentials of composites gradually moved to high potential and the reduction potential gradually moved to low potential with the increasing content of CNTs, which was ascribed to the fact that the ability to obtain the electrons of composites decreased and the ability to loss the electrons enhanced after adding CNTs.
  • Abrasion performance of?epoxy?resin composite filled with cenospheres
    Li-Miaomiao Chen Ping
    . 2015, 46(22): 27-0.
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    Epoxy resin?composite filled with fly ash?cenospheres were synthesized. The abrasion loss and hardness of specimens were measured using an abrasion tester and a Shore hardness tester, respectively. And the effect of curing process, curing agent content and?cenospheres content on abrasion performance of specimens was discussed by analyzing the micrographs of the worn surfaces. The results show that the amount of polyamide?650 obviously affects the hardness of specimens. And with the increase of polyamide?650, the hardness of specimens increases and the abrasion loss decreases. The abrasion loss of specimens are different with the different curing process. The composite obtained at the curing temperature of 120℃ and curing time of 1h has the better abrasion performance. With the increase of amount of fly ash cenospheres, the abrasion loss of the specimen decreases first and then increases. When the mass fraction of cenospheres is 20%, the cenospheres are dispersed uniformly into the matrix，and have a good consistency with matrix, which result in low abrasion loss and better abrasion performance.
  • Synthesis , characterization and antibacterial activity of cationic nanopolymer
    zheng-hui WANG
    . 2015, 46(22): 28-0.
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    Cationic nanopolymers were prepared by micellar copolymerization of methylmathacrylate (MMA) with methacryloxyethyldimethylhexadecyl ammonium bromide (MDHB). The particle size, zeta potential and molecular weight of the polymers were measured，and the structures were characterized by FT-IR, 1H NMR and TG. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration(MBC) of this kind of polymer against E.Coli and S.aureus were tested using a broth dilution test. The results shown that the concentration of MDHB plays a key role in structural characteristics and antibacterial properties of the products. With increasing of MDHB in recipe, particle size and antibacterial activity increase, zeta potential and molecular weight decrease. The polymers have good thermal stability, so they can be blended with common polymer matrix to prepare antibacterial materials. Therefore this kind of polymer is expected to be a promising antibacterial agent for development and application.
  • The preparation and study of melt-stretched Polypropylene/Al2O3 compound microporous membrane
    . 2015, 46(22): 29-0.
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    Polypropylene/Al2O3 compound microporous membranes were prepared based on melt-stretching mechanism. Universal tensile testing machine，DSC and SEM were employed to characterize the properties and structure of the cast films and stretched microporous membrane. Results indicated that Al2O3 could improve the electrolyte uptake and mechanical properties of PP/Al2O3 microporous membrane. But when the Al2O3 content was higher than 2%, the elastic recovery of precursor films declined significantly and the obtained microporous membrane showed bad microstructure, poor permeability and lower porosity.
  • Preparation and characterization of silk fibroin/nano-hydroxyapatite composite scaffold
    . 2015, 46(22): 30-0.
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    Porous silk fibroin scaffold was first prepared by using spunlacing technique, then nano-hydroxyapatite (HAP) /silk fibroin composite materials were synthesized via in-situ mineralization. HAP showed a uniform rod-like structure, but only granular structures were observed without silk fibroin scaffold, indicating that silk fibroin scaffold can induce the formation of rod-like structures. This is attributed to the electrostatic interactions between carboxyl groups of silk fibroin and Ca2+ in the solution. Thus silk fibroin scaffold plays a dual role of polymer composites substrate and template for HAP in-situ growth. The structure and properties of the composites were characterized by using infrared spectroscopy, X-ray diffraction and mechanical testing. Infrared spectra showed the presence of hydrogen bonding interactions between PO43- of HAP and -NH2 of silk fibroin, while X-ray diffraction patterns suggested that the composites maintained the β-sheet structure and crystallization properties of silk fibroin scaffold. Thus the composites resulted with good mechanical properties and porous structure, which is helpful in osteoblast proliferation and the use as bone repair scaffolds.
  • Effect of SSC coating on the oxygen permeability of BaCo0.7Fe0.2Nb0.1O3-δ membrane under CO2-containing atmosphere
    Cheng-Zhang WU
    . 2015, 46(22): 31-0.
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    Porous Sm0.7Sr0.3CoO3-δ (SSC) coated BaCo0.7Fe0.3-xNbxO3-δ (BCFN) perovskite membrane was prepared by solid phase reaction method, and the effect of SSC coating on the oxygen permeability of BaCo0.7Fe0.2Nb0.1O3-δ membrane under CO2-containing atmosphere was systematically studied. The results demonstrate that the porous SSC coating enhances the oxygen permeability of BCFN under CO2-containing atmosphere. The oxygen permeation flux of non-coated BCFN membrane using 5 % CO2 as sweep gas is decreased by 85 % after 60 h test, whereas the oxygen flux of SSC-coated BCFN membrane is only decreased by 31 % at the same condition, which is still 1.3 ml?cm-2?min-1.
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