30 September 2012, Volume 43 Issue 18
    

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  • Research process of solvent refining of silicon for the preparation of solar grade silicon
    Jingwei Li;Zhancheng Guo
    . 2012, 43(18): 1-0.
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    The rapid development of photovoltaic industry results in the great demand of silicon feedstock for solar cells. Solvent refining of silicon as a new purification process, will be more emphasized. Solvent refining of silicon is a purification process in which recrystallized silicon takes place from the supersaturated melt depending on the segregation behavior of different elements between silicon and melt. In this paper, the research process on the main solvent systems, such as Al-Si、Sn-Si、Cu-Si、Fe-Si、Ca-Si et al, is introduced in detail presently. Comparisons with the advantage and disadvantage of different solvent systems are discussed. At last, some suggestions were put forward for further purification.
    • 研究与开发
  • Experimental Investigation on the Microcapsule Preparation by Supercritical Impinging Stream Technology
    Wei-Wei Wei Wei;;;
    . 2012, 43(18): 2-0.
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    Supercritical fluid impinging technology (SFIT) was proposed as a novel microparticle coating process, which combines supercritical fluid technique with impinging steam technique. The process was investigated using ultrafine glass beads as the core particle and paraffin as the coating material. The effects of the operation parameters, such as pressure, temperature, impinging distance and temperature before express were investigated. As the result, the optimal operation condition was: pressure of 20MPa, temperature of 75℃, impinging distance of 70mm, and pre-expansion temperature of 140℃. A number of techniques were used for the characterization of the microcapsules. A scanning electron microscope (SEM) was used to observe the morphology of the particle surface. The microcapsule size distribution is measured by laser particle size analyzer (LPSA), and differential scanning calorimeter (DSC) measurements were conducted to determine the apparent coating rates of microcapsules. The advantages of SFIT enhance the mass transfer and heat transfer, which prevent particles agglomeration. There is, of course, coating of microparticle by SFIT is demonstrated to have enormous potential.
  • Preparation of pH sensitive and porous hemicellulose hydrogels for drug release
    ;Xiao-Feng Sun
    . 2012, 43(18): 3-0.
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    In this paper, porous hemicellulose-grafted-poly (acrylamide) hydrogels was prepared using PEG as porogen and free radical polymerization. The structure and surface morphology of these hydrogels were analyzed by FT-IR and SEM. pH-sensitive of hydrogels and effects of monomer ratio, weight of PEG used, PEG molecular weight and cross-linker weight on equilibrium swelling ratio were also discussed. Finally, release performance of hydrogels using methylene blue as model drug was studied. These experimental results indicated that the porogen PEG did not the polymerization; the hydrogels had porous structure and excellent pH-sensitivity, which is expected to become a good drug carrier.
  • Preparation and Evaluation of Non-packing Hemostatic Base on Chitosan
    Tao Zhang
    . 2012, 43(18): 4-0.
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    Abstract：Hemostasis is one common problem in otolaryngology. Hydrogels derived from natural proteins and polysaccharides are ideal hemostatic materials since they resemble the extracellular matrices of the tissue comprising various amino acids and sugar based macromolecules. This work presented the hydrogel microspheres based on chitosan and hyaluronic by the spray-drying method. Perfectly spherical hydrogel microspheres were obtained in the size range of 1-2μm. The microspheres reach the balance swelling in 15 minutes, and the swelling ratio reaches 30 times of the original. The animal test showed that there was little serious negative effect of the Chi-HA microspheres on the normal nasal mucosa. And the Chi-HA microspheres were more safety than sponge when used in packing nasal cavity.
  • Microwave-assisted polyol synthesis and magnetic properties of monodisperse Ni1-xZnxFe2O4/MWCNT nanocomposites
    Huaqiang Wu
    . 2012, 43(18): 5-0.
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    Ni1-xZnxFe2O4/MWCNT nanocomposites (x=0.4 0.5, 0.6) with controllable composition have been successfully fabricated via microwave-assisted polyol route using triethylene glycol solution (TREG) as solvent. The structure and morphology of the final products were characterized by XRD, SEM, TEM and EDX. The magnetic properties were measured by VSM. The influence of microwave power and microwave time on loading has also been investigated. The results show that the spinel Ni1-xZnxFe2O4 nanoparticles with a face-centered cubic structure appear to be a monodisperse distribution on MWCNTs. The average sizes of the nanopaticles were about 6 nm. The magnetic properties of Ni1-xZnxFe2O4/MWCNT nanocomposites vary with ferrite composition. The saturation magnetization (Ms) of Ni1-xZnxFe2O4/MWCNT nanocomposites increases firstly and then decrease with Zn content increasing. Ms reaches a maximum value when x equals to 0.5. The nanocomposites exhibit low coercivity (Hc) at room temperature, which can be a typical characteristic of superparamagnetic.
  • Thermochromic Properties and Mechanism of BCG-rare earth Composite Materials
    Cheng-Wu FU;;chen ming qing
    . 2012, 43(18): 6-0.
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    A series of thermochromic composite materials composed of bromocresol green (BCG) and rare earth metal ions were prepared. The effects on thermochromism by the sort and ratio of delomorphic reagent and solvent were studied. Based on the identification of FTIR、UV-Vis and DSC analysis, the thermochromic mechanism of composites were summarized for electron gain or loss among the molecules. At room temperature, quinonoid BCG is coordinated with rare earth metal ions. After warming, the complex was separated, lactone ring structure is recurring on BCG. Therewith, the color inversion can be realized with temperature variation.
  • The Post-drawing of Electrospun Silk Fibroin Mats in Ethanol Aqueous Solution
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    . 2012, 43(18): 7-0.
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    Regenerated silk fibroin mats were prepared using electrospinning method and post-drawn in ethanol aqueous solution to improve mechanical properties. The effects of ethanol volume fraction of the solution on the morphology, secondary structure and properties of the mats were investigated. It was found that with the increase of the ethanol volume fraction, the β-sheet content of the mats increased. The mats, which were post-drawn 1.11x and then immersed 120 min in 90 vol% ethanol, achieved a breaking strength of 2.64 MPa and a breaking elongation of 12.1 %.
  • Grain-size effect on the preferred orientation of TiC/α-C:H thin films
    yadong suwang xiangming;;
    . 2012, 43(18): 8-0.
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    The grain-size effect on the preferred orientation has been revealed in TiC/α-C:H nanocomposite films grown by magnetron sputtering, in which the grain size of TiC can be adjusted through changing C content in films. The finding is that the preferred orientation of films is significantly affected by the grain size, and the crystallographic orientation changes from face-centered cubic (fcc) TiC (111) to (200) as the grain size of nanocrystallite TiC decreases from ~22.3 to ~4.7 nm. This size-dependent preferred orientation is explained via thermodynamic calculations, from which the size-dependent Gibbs free energies are found to be a key factor that controls the texture development in thin films if the grain size in films is sufficient small.
  • Study on the Applications of CaSO4 Whiskers In PVC Composites
    Shu-hua ZHANG
    . 2012, 43(18): 9-0.
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    Structures of CaSO4 whisker A, B and C were characterized by IR, XRD and the optical microscope. The results showed that the ratios of length to diameter of CaSO4 whisker A, B and C are 5.2, 9.1 and 3.3. The modified CaSO4 whisker B has perfect crystal structure and less defects. Three kinds of composites with CaSO4 whisker A, B and C were prepared separately and the mechanical properties, insulation resistances and static thermal stability time at 200 ℃ of three composites were investigated, and the degradation processes were analyzed by TG at 50-400℃, N2 atmosphere by comparing with CaCO3 / PVC. The dispersing states of three whiskers were observed in the composites by means of optical microscope and SEM. The experimental results indicated that the toughening and reinforcing effects and thermal stability of long CaSO4 whiskers A and B /PVC composites are better than those of CaSO4 whisker C, CaCO3 /PVC and gas phase method silica aerogel/ PVC. The modified CaSO4 whisker B has the best consistency and interfacial configuration with PVC resin and the tensile strength, elongation at break and thermal stability time of composites have reached 23.20 Mpa，380.85% and 95 min. In a word, The excellent comprehensive properties will be obtained when the whisker’s ratio of length to diameter is big, the crystallinity is good and the modification.
  • Study on piezomagnetic properties of polygonal amorphous powders/silicone rubber composite films
    Jia ZHOU;
    . 2012, 43(18): 10-0.
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    Abstract: The piezomagnetic films were prepared by FeCuNbSiB or FeSiB amorphous powders and silicone rubber. The piezomagnetic properties of the samples were tested by the 4284A impendance analyzer. The results show that both FeCuNbSiB/ silicone rubber films and FeSiB/ silicone rubber films have excellent piezomagnetic properties. For FeCuNbSiB/ silicone rubber films, the composite films have sensitive piezomagnetic properties when the compress stress being low 0.6MPa and test frequency being low 200kHz. The piezomagnetic property is always good between 0~1.45 MPa for the FeSiB/ silicone rubber films. It is also found that the content of powders is higher, the piezomagnetic property of films is better, especially when the content is 83.3%, the piezomagnetic property is up to the maximum. The piezomagnetic property of FeCuNbSiB/ silicone rubber films is superior to FeSiB/ silicone rubber films under the same conditions.
  • Effect of pH on Size and Dispersion of CMC/Eu Nanocomposites with High Fluorescence Intensity
    Jun Ye;Yuan Guo;Jian XIONG
    . 2012, 43(18): 11-0.
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    In the paper，CMC/Eu nanocomposites were synthesized under microwave-assisted by reacting with Eu3+ and CMC，a kind of biodegradable polymer．The structure, surface topography and luminance were characterized by FTIR，SEM，AFM and fluorescence spectrum．Effect of pH on Sizes and distribution of CMC/Eu nanocomposites was also discussed in detail. The results showed that fluorescence intensities of CMC/Eu nanocomposites is stronger than that of bulk CMC/Eu; particle sizes of CMC/Eu nanocomposites were from 150 to 500nm; moreover, the particle sizes decreasing and particle distribution being more uniformly with pH increasing. The particle size was smallest and well-distributed when pH is13.4．
  • Synthesis and photoluminescence property of Ba3V2O8:Eu3+ nanoflowers
    ;Ya FUYUAN Jin-Hai;;;
    . 2012, 43(18): 12-0.
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    Ba3V2O8:Eu3+ nanoflowers have been obtained by the composite hydroxide mediated (CHM) method. Scan electron microscope and transmission electron microscope display that the flower-shaped crystals are composed of nanosheets with thickness of ~20 nm. Photoluminescence spectrum of the Ba3V2O8:Eu3+ nanoflowers exhibit red emission centered at 591 and 612 nm, which shows function of red light conversion. The mechanism of light emission of the Ba3V2O8:Eu3+ nanoflowers was discussed.
  • Preparation and Properties of composite anode materials CuxCo1-x-SDC for SOFC by GNP method
    . 2012, 43(18): 13-0.
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    GNP method was adopted to prepare CuxCoyO-SDC series anode materials. Electrochemistry performance was tested by using an electrochemical workstation. CuxCoyO-SDC was characterized by using particle size analyzer, XRD, SEM, EDS, IR and TG-DTA. The research results show that Co is added in Cu matrix anode as a good catalytic so that the anode shows excellent catalytic activity and cell electrochemical properties are improved.
  • Analysis of Processing Rheological Property of PBS/Poplar Wood Flour Composites and Its Applications
    Yue-Jun LIU ;
    . 2012, 43(18): 14-0.
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    The influence of different temperature and contents of poplar wood flour (WF) on the rheological behavior of the composites was researched through measuring the rheological behavior of the poly(butylene succinate)(PBS) and the PBS/WF composites by advanced capillary rheometer. Using rheological properties of composites as a reference, changing processing technology, PBS/WF composites were prepared by melt blending and injection molding, after that, we tested the performance of the samples. The results showed that: with the increase of the amount of WF, the melt flow properties of the composite had a great decline and the processing temperature range became more and more narrow; Different processing technologies had a certain impact on the performance of PBS/WF composites. Take mechanical and rheological properties into consideration, the optimum processing temperature of the PBS/poplar wood flour composites are 120 ℃、125 ℃、125 ℃、130 ℃、135 ℃ with 30 %、35 %、40 %、45 %、50 % of poplar wood flour respectively.
  • Preparation and microwave-absorbing properties for the Ba0.6Sr0.4TiO3 / Polyaniline composite
    . 2012, 43(18): 15-0.
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    The Ba0.6Sr0.4TiO3/ polyaniline composite was prepared by in situ polymerization method under the ultrasonic field. The structural characteristics, morphology and electromagnetic properties of the composites were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and HP8510 network analyzer, respectively. The results indicate that HCl doped polyaniline has some degree of crystallinity. There is some interaction between the Ba0.6Sr0.4TiO3 particles and polyaniline chains. The imaginary and real parts of complex permittivity of the Ba0.6Sr0.4TiO3/ polyaniline composite are higher than those of polyaniline from 8.2 to 12 GHz. The dielectric loss tangent of Ba0.6Sr0.4TiO3/ polyaniline composite is higher than that of polyaniline from 9.8 to 12.4 GHz. The composite shows better electromagnetic wave absorbing property, with a minimum reflection loss of -14 dB and a bandwidth of -10 dB over the extended frequency range of 5 GHz.
  • The Effect of Mg on the Microstructure and Electrochemical Properties of A5B19 type La0.8-xGd0.2MgxNi3.3Co0.3Al0.1(x=0-0.4) Hydrogen Storage Alloys
    ;
    . 2012, 43(18): 16-0.
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    La0.8-xGd0.2MgxNi3.3Co0.3Al0.1 (x = 0-0.4) hydrogen storage alloys were prepared by induction melting followed by annealing treatment for16 hours at 1273 K under high purity argon atmosphere. The effect of Mg on the microstructure and electrochemical properties of La0.8-xGd0.2MgxNi3.3Co0.3Al0.1 (x = 0-0.4) were investigated systematically by means of X-ray diffraction (XRD), electron probe micro-analysis (EPMA) and electrochemical measurements. The results showed that all these alloys mainly consisted of Pr5Co19-type, PuNi3-type, Ce2Ni7-type and CaCu5-type phase. With increasing Mg content, the main phase of Pr5Co19-type abundance first increased and then decreased and the maximum phase 88.23 wt.% abundance when x was 0.15. The plateau pressure of P-C-T curves rose gradually and became flatter when x increased. The lowest plateau pressure of alloys was about 0.02 MPa and the hydrogen storage capacity was 1.334 wt.% when x was 0.15. The electrochemical measurements showed that all these alloys had a good activation performance, and then the discharge capacity of the alloys first increased and the decreased with the increase of Mg, and also the maximum discharge capacity of the alloys reached 377.9 mAh/g when x was 0.15. After 100 charge-discharge cycles, the discharge capacity retention rate S100 of the alloy electrode (x = 0.15) reached 90.2%. Among the alloys studied, the La0.65Gd0.2Mg0.15Ni3.3Co0.3Al0.1 alloy possessed the best electrochemical properties.
  • Studies on adsorption of methyl orange from aqueous solutions onto Mg/Al-LDH
    Lu-Hong ZHANG li zhang;yan jian hui
    . 2012, 43(18): 17-0.
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    Abstract:Mg/Al-LDH was prepared by co-precipitation and hydrothermal reaction. Under the experimental conditions：hydrothermal reaction temperature = 180 ℃; reaction solution pH = 9?10; reaction time = 4 h; concentration of the all reactants = 0.1 mol/L, the effect of Mg/Al molar ratio on the methyl orange adsorption performance of MgAl-LDH was firstly investigated. Moreover, the adsorption performance of materials after regeneration was studied. The results showed that the highest methyl orange adsorption performance was achieved on MgAl-LDH when the Mg/Al molar ratio was at 2.5:1. Under the optimum experimental conditions, a high adsorption capacity of 83.33 mg/g of methyl orange on 2.5:1MgAl-LDH could be detected. The materials obtained can be reused after calcination at 400 ℃. Furthermore, the adsorption performance did not change markedly even after three cycles. In addition, in order to analyze the adsorption mechanism, the materials prepared were characterized in detail with SEM and TG-DTA techniques.
  • Preparation and Thermal Stability Research of Mesoporous Carbons with Different Pore Structures
    Peng Li
    . 2012, 43(18): 18-0.
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    In this manuscript, two kinds of mesoporous carbons (MCs) with different pore structures were prepared by soft-templating method. The microstructue of MCs was studied by high resolution transmission electron microscope, Nitrogen adsorption–desorption isotherms and Small angle X-ray scattering. Results show that MCs with cylinder pore structure has the better thermal stability than that of MCs with ink-bottle like pore structure.
  • nanofibers and their influence on cellular adhesion, proliferation and migration
    . 2012, 43(18): 19-0.
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    The scaffold compositions played different roles on cellular biological functions. In this study, we developed polycaprolactone (PCL) based nanofibers composed of natural protein and polysaccharides (hyaluronan (HA), silk fibroin (SF)) via electrospinning technology. These nanofibers were characterized by scanning electron microscopy (SEM) and contact angle. Furthermore, we evaluated the potential of different composite nanofibers as tissue engineering scaffolds. In vitro cultivation of human primary skin fibroblasts on the SF-based scaffolds showed a significant increase in cell proliferation. A significant number of cells were found to have well-developed cytoskeleton on PCL/SF nanofibers. Addition of HA component transformed current PCL and PCL/SF components into hydrophilic fibers. Importantly, HA-based scaffolds significantly enhanced cell filopodia protrusions and migration in vitro. PCL/SF/HA nanofibers could combine the advantages of SF and HA. These findings suggest that such multiple blended nanofibers may offer possibilities to tissue engineering application.
  • Study on acetylated Chitosan microspheres as potential chemoembolizating materials
    Xuan ZHOU;Wei-Fang LIU;Chao FENG;;Xiao-Jie CHENG;
    . 2012, 43(18): 20-0.
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    Chitosan microspheres (CMs) and acetylated Chitosan microspheres (ACMs) with smooth surface and good dispersion are prepared by emulsion cross-linking methods. It is showed that characteristics of ACMs better than CMs via a series experiment such as swelling, degradation in vitro and the cytotoxicity. Rabbit ear artery is successfully embolized with ACMs. After 15d, arteriole atrophy disappears in ear tip, surrounding tissues is coagulation necrosis and partly fall off, edge skin border with necrotic tissue become atrophy and thickening. The result shows that ACMs have embolic effect on vessel as a potential embolizating agent.
  • Evaluation on the blood compatibility and cell compatibility of medical high nitrogen nickel-free stainless steel in vitro
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    . 2012, 43(18): 21-0.
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    Effects of high nitrogen nickel-free stainless steel on the adhesion of Human Umbilical Vein Endothelial Cells (HUVECs ) and blood platelets were investigated. The blood platelets adhesion test and blood hemolysis rate were used to evaluate the blood compatibility of high nitrogen nickel-free stainless steel. Human umbilical vein endothelial cells (HUVECs) were cultured in vitro, using MTT cytotoxicity test, cell adhesion test, to evaluate the cell compatibility of high nitrogen nickel-free stainless steel. Results show that the hemolysis rate of high nitrogen nickel-free stainless steel is well below the accepted threshold value of 5％, but the effect on platelet adhesion is not obvious; The number of HUVECs adhesion on surface of high nitrogen nickel-free stainless steel were significantly more than that on the surface of titanium, and the cells in the surface shows a good growth situation. MTT test shows that both the high nitrogen nickel-free stainless steel and titanium alloy have no obvious effect on the HUVECs.
  • The Electrochromic Properties and electrochromic divics of 4,4’-biphenyl Dicarboxylic Acid Ester
    Xue-Mei HUANG
    . 2012, 43(18): 22-0.
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    six 4,4’-biphenyl dicarboxylic acid ester were synthesized with biphenyl as raw material and their structure were confirmed by 1HNMR, IR. Their electrochemical properties and spectrachemical properties were examined by electrochemical working station and UV-Vis spectra. It was found that 4,4’-biphenyl dicarboxylic acid ester as electrochromic material in the composite electrochromic device (ECD) showed reversible、clear color changes from yellow-green to red when the voltage from 3.0V to 3.6V. The synthesized 4,4’-biphenyl dicarboxylic acid esters are promising candidate materials for visible ECDs, for their outstanding electrochromic behaviors and the cheap original stuff and short synthetic routes.
  • Influence of iron powder purity and particle size on the magnetic properties of phosphated iron soft magnetic composites
    Fa-Chang LI xuequan liu;;;;
    . 2012, 43(18): 23-0.
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    This paper investigates the effect of iron powder purity and particle size on the magnetic properties of phosphated iron soft magnetic composites(SMC). The results showed that the phosphating process give rise to a large coverage of the iron powders surface by the iron phosphate coating. The density and permeability of phosphated iron samples shows an increase with increased the iron powder purity or particle size. The sample with higher iron powder purity exhibits lower hysteresis loss. With increase in the particle size, magnetic loss increases significantly at medium and high frequencies, and the higher the frequency the more obvious.
  • Synthesis and properties of poly(propylene ethylene carbonate) coated stent coating
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    . 2012, 43(18): 24-0.
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    The biodegradable poly(propylene ethylene carbonate) (PPEC, Mw=229.338kDa) was synthesized using zinc glutarate catalyst and investigated as drug-loaded coating materials for the first time in this paper. 1H NMR spectra show the contribution of ethylene oxide and propylene oxide is 6:4 and the carbonate content is 76.7% in PPEC molecular formula. The elongation at break is 550% by stress - strain test. Attenuated Total Reflectance - infrared spectroscopy (ATR-FTIR) analysis of sirolimus, PPEC and sirolimus-loaded PPEC coating show that no chemical reactions happene between sirolimus and PPEC. After balloon expansion experiment, no delamination or destruction of the coating is observed by SEM. In vitro drug release behavior reveals that drug release of drug-eluting stent is over 60 days in PBS (0.05M, pH = 7.4) solution. All the experiment results show that PPEC as a stent coating materials has broad application prospects.
  • Preparation of Al2O3/TiO2/PVDF hybrid ultrafiltration membrane and its performances research
    . 2012, 43(18): 25-0.
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    The polymer polyvinylidene fluoride (PVDF) membranes were modified by blending into nanometer particles in order to improve its hydrophilic property and anti-fouling performances in water treatment. The organic macromolecule blended ultrafiltration (UF) membranes modified by the inorganic nanometer TiO2 and Al2O3 were prepared by the phase inversion process. The cup ultrafiltration set was employed to study the effects of nanometer particles addition on the permeation performances of hybrid membrane. The experimental results show that the microstructure and morphology of organic membranes are not changed by nanometer particles addition; the hybrid membrane water flux increases 79.5% than that of organic membrane with 3% nanometer particles addition and the proportion of TiO2 and Al2O3 is 1:1,but its rejection rate is not change. The mechanical strength of the hybrid membrane increase 41.6%; pure water contact angle of hybrid membrane dropped from78.68° to 50.54°, which improved the hybrid membranes hydrophilic. The hybrid membrane average pore size is large than that of organic membrane and the pore size distribution is more uniform. The hybrid UF membrane has not only maintained PVDF membrane’s favorable performances but also its intensity, hydrophilic and anti-fouling performances have been improved.
  • Three-dimensional flower-like Sr2MgSi2O7:Eu2+ Blue phosphor and its luminescence properties
    . 2012, 43(18): 26-0.
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    three-dimensional flower-like Sr2MgSi2O7:Eu2+ blue luminescent materials were successfully synthesized by Sol-Gel method with glucose as surfactants. The phase structure, morphologies and luminescence properties of Sr2MgSi2O7:Eu2+ were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL) .The results show that the appropriate amount of concentration of glucose can change the morphologies of product and improve the luminescence properties but had no pronounced effects on structure of the products. When the concentration of glucose was 0.03g/ml, shape of products changes from flakes or chunk to the obvious flower-like patterns at 1200℃ for 2h. The products emit bright 469nm blue fluorescence when excited by 355 nm ultraviolet radiation, and the luminous intensity is the strongest.
  • Preparation and characterization of monodisperse polysilsesquioxane microspheres with different organofunctional groups
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    . 2012, 43(18): 27-0.
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    Highly uniform and monodisperse methyl-functionalized polysilsesquioxane microspheres(MPSQ)、vinyl-functionalized polysilsesquioxane microspheres(VPSQ) and thiol-functionalized polysilsesquioxane microspheres(MPPSQ) were prepared by emulsion polymeration. The morphology, size distribution, and state of aggregation were characterized by SEM, DLS, FT-IR, XRD. The thermodecomposition and hydrophobicity of these microspheres were investigated with TGA and water contact angle measurement. Our research turned out that the organofunctional groups play a key role in thermostability and hydrophobicity of microspheres, MPSQ and VPSQ possess better thermostability than MPPSQ, the order of hydrophobicity is as follows: MPSQ>VPSQ>MPPSQ. The formation mechanism of polysilsesquioxane microspheres may be explained by nucleation theory. First, the silanol groups come out when the precursor is catalyzed by triethylamine, then the polycondensation of silanol groups begin and a large number of nuclei are generated, and all the nuclei start to grow up by absorption of silanol groups in the solvent. Finally, monodisperse polysilsesquioxane microspheres are formed. The nuclei generation process and nuclei growth process are competing with each other during the reaction. The reaction condition determines which process dominates the reaction.The particle will turn smaller and less monodisperse as the reaction temperature rises.
  • Research on the ladder type function photon crystals
    . 2012, 43(18): 28-0.
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    In this paper, we study one-dimensional function photonic crystals (PCs) of ladder type, and give the effect of different incident angle on dispersion relation and transmissivity. We compare the function PCs with convention PCs and find there are defect model obviously, but the number of defect model become small, and the intensity is weak in the function PCs. Further, we research the characteristic of light transmission in the ladder type function PCs with defect and without defect. With defect, we find the distribution of electric field can be increased or decreased, which is different from the convention photonic crystals electric field distribution increased locally. The new characteristic of function photonic crystals will be applied widely.
  • Synthesization and Structure Research of Acrylonitrile/ Acrylamide by Aqueous Deposited Polymerization
    . 2012, 43(18): 29-0.
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    Acrylonitrile/acrylamide copolymer was synthesized by the continuous aqueous deposited polymerization using acrylamide as comonomers. The effects of the acrylamide on the polymerization and copolymer structures were investigated. From the results, it showed that the reactivity of acrylamide was higher than acrylonitrile, tended to be homopolymerization reaction, which can decrease its molecule weight and increase the conversion rate of polymerization. The chain tacticity can be changed slightly by a small amount of acrylamide, and the crystallinity of PAN can be improved, the crystallite dimension can be decreased.
  • The Stabilizers of Dispersion Polymerization in ScCO2
    Xing HUANG;;
    . 2012, 43(18): 30-0.
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    With the increasing serious of environmental pollution and the increasing awareness of environmental protection , people are trying to find a new non-toxic and non-polluting material instead of organic solvents in order to reduce the serious environment pollution caused by chemical organic solvents. As a supercritical fluid, supercritical CO2 could excellently replace many harmful, toxic, volatile, flammable organic solvents in environmental chemistry, The composition and the mechanism of the dispersion polymerization system in supercritical carbon dioxide were introduced in this paper. And the action mechanism of the stabilizer in the dispersion polymerization was also discussed. The research situation of low toxicity organic silicon and non-fluoride & non-silicon stabilizers, were introduced in detail. Finally, the main problems of the current stabilizer were reviewed and the tendency of development on the dispersion polymerization was forecasted.
  • Preparation and Cytocompatibility Study on Electrospun Poly(D, L, lactic acid) Fibrous Scaffolds
    Ya FU
    . 2012, 43(18): 31-0.
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    Electrospun poly(D,L, lactic acid) (PDLLA) superfine fiber has become one of the hot spots regarding scaffolds materials in tissue engineering, due to its high porosity, tunable pore size and structure, as well as good biocompatibility. In this study, we investigated the factors including concentration, solution feeding rate, applied voltage and drying methods that affecting the morphology of PDLLA fibrous scaffolds. The optimum process parameters were determined: solution concentration was 0.20g/ml, solution feeding rate was 0.8ml/h, applied voltage was 12kv. After lyophilization, uniformly distributed PDLLA fibers with diameters of 500nm-900nm were obtained. In vitro cell morphology observation showed that PDLLA fibrous scaffolds having good cytocompatibility.
    • 综述
  • To immobilize protein with LB films and its application in biosensors
    Zhu-Ping HAN;
    . 2012, 43(18): 32-0.
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    Abstract: LB(Langmuir- Blodgett) technique is an advanced technique to design novel functional materials, because it can control thickness and well-ordered films in molecular level. Biofunctional protein immobilized with LB films can be widely applied in biosensor, bionic membrane and biocatalysis areas. This review summarizes the methods of immobilizing, influence factors and application in biosensors of protein LB films. Keywords: LB film, enzyme immobilization, protein, biosensors, functional materials
  • Progress of gold-coated core-shell magnetic nanoparticles
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    . 2012, 43(18): 33-0.
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    Gold-coated core-shell magnetic nanoparticles, which have both the properties of magnetic nanoparticles and the surface chemical properties of Au nanoparticles, have attracted much attention in recent years. This review has summarized the preparation and the application of two kinds of these composite nanomaterials, and their prospect is also addressed.
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