15 November 2014, Volume 45 Issue 21
    

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    工艺 技术
  • . 2014, 45(21): 1-0.
    Abstract ( ) Knowledge map Save
    According to the characteristics of lower sealing temperature of the vacuum plate glass and coefficient of thermal expansion of phase match between the glass and the sealing solder, the experiment selected the sealing solder of the PbO-TiO2-SiO2-RxOy system. The edges of the vacuum plate glass were sealed with welding process under vacuum. The microstructure and phase composition of sealing edges of the vacuum plate glass were analyzed for EBSD, EDS and XRD. The associative property and stability at the interfaces between the sealing layer and the glass were studied. And the sealing solder of the vacuum plate glass was experimented with shear strength and air tightness, and measured shear performance and airtight performance. Sealing mechanism of the vacuum plate glass was explored. The results show that the interface between the glass and the sealing solder is clear, related closely and sealing effect is well. The sealing layer divides into the wetting layer for reacting with the interface and the melting layer, and the thickness is 7~9 μm and 180~190 μm respectively. The interface appears element migration. The wetting layer for reacting with the interface creates few PbTiO3. The sealing layer barely exists obvious cracks and exists few disconnected pore, but not affect its airtight performance. Air tightness of the sealing solder reaches 1.0×10-9 Pa?m3/s.
  • 研究 开发
  • . 2014, 45(21): 2-0.
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    Fe52Co34Zr7B6Cu1 amorphous alloys thin strip were prepared by single-roller-quenching method. We treated Fe-based amorphous alloys by mid frequency pulse magnetic field. Fe-based amorphous samples before and after treated were measured by homemade magnetostrictive coefficient measurement system and Mossbauer spectroscopy. The results indicated that amorphous strip were nanocrystallized after treated by pulse magnetic field and crystalline phase mainly α-FeCo. Magnetostrictive coefficient changed first decrease and then increase with the pulsed magnetic field increased. It indicated that the magnetic properties of dual phase alloy for pulsed magnetic field is selective. The results of Mossbauer tests indicated that the sample after pulsed magnetic field treated still showed obvious amorphous characteristics and the percentage of the amount of crystallization were 9.9%, 17.2% and 28.3% with the enhancement of pulsed magnetic fields.
  • Duo-jie Gengzang
    . 2014, 45(21): 3-0.
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    Zn1-xFexO (x=1.0%, 3.0%, 5.0%) thin films deposited on Si were successfully prepared by radio frequency magnetron sputtering. The microstructure, chemical composition, valence states, morphology and ferromagnetism of the films had been investigated by X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning electronic microscopy (SEM) and vibrating sample magnetometer (VSM), respectively. The results indicate that highly c-axis preferential orientation of Zn1-xFexO films with wurtzite phase was successfully fabricated by Fe doping. Valence state of Fe in Zn1-xFexO films is a mixture of 2+ and 3+. The results of VSM experiment proved the ferromagnetism of Zn1-xFexO at room temperature. The sources of ferromagnetic are attributed to magnetic polaron which induced by the magnetic ions and the vacancy defects.
  • 工艺 技术
  • ; ;;
    . 2014, 45(21): 5-0.
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    Polypropylene non-woven fabric was used as substrate, acrylic acid was grafted onto the PP films via UV irradiation, followed by amidate, hydrazide, azidation and coupling gelatin molecules via UV irradiation. The material with good adsorption performance for tannin acid was obtained. Weighing method, Fourier transform infrared spectroscopy, Thermogravimentry-differentlal thermogravimetry and Scanning electron microscopy were used to measure functional groups, characterize structures and hygroscopic property of the substrate, intermediate and final products. The results show that all the reactions introduced target groups according to the prospection, the maximum adsroption of modified material for tannin acid was 84.30mg/g.
  • ;
    . 2014, 45(21): 6-0.
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    Humidity-controlling material was prepared with chitin and sodium carboxymethyl cellulose (CMC) as the matrix material, mixed with silica gel and LiCl. Factors influencing performance of humidity-controlling material have been investigated. The structure and performance of the materials were characterized by means of analytical methods, such as FT-IR and SEM. The results indicated that hygroscopic capacity of the humidity-controlling material when the material was prepared with CT,CMC, LiCl,silica gel in the ratio of 2: 2: 2: 1in mass could reach 134%、70%、45% under different humidity (80%、60%、40% RH) respectively. It also had great moisture capacity.
  • Jin-Long LIU
    . 2014, 45(21): 7-0.
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    Gradient high silicon steel thin sheets with thickness of 0.20mm were successfully produced by the rolling and annealing method, including hot rolling bonding, cold rolling, and annealing. Microstructure and texture evolution was investigated by means of SEM and X-ray diffraction. Microstructure of hot-rolling-bonding shows obviously layered distribution, the composite interface is closely metallurgical bonding and no cracking appears even after 83% cold rolling. Strong α and γ fibers develop in the hot and cold rolled state, and γ fiber dominates the recrystallization texture. Cold rolling and annealing texture is gradient distribution through the thickness, which can be attributed to the difference of chemical composition and initial hot-rolled texture on either side of the composite interface as well as the inhomogeneity of cold deformation.
  • Cheng Wang
    . 2014, 45(21): 8-0.
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    With Chromium slag as main raw material, the shaly of City Yichang as the correction material for the preparation of radiation shielding aggregate, the effect of the composition of raw materials, preheating, temperature rise rate, calcination for radiation shielding performance of aggregates and the mineral composition is researched. The successful preparation of radiation shielding aggregates whose apparent density is higher than 2.30 g/cm3, compressive strength is higher than 5 MPa, bibulous rate for 1 hour is lower than 8%, and linear attenuation coefficient achieves 0.172 cm- 1 by 0.662 MeV Gamma-Ray is completed.
  • Jun LI
    . 2014, 45(21): 9-0.
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    The polyvinyl alcohol (PVA) fiber was adopted as reinforcing material, the different fly ash dosages, particle sizes of silica sand, fiber contents and methods of curing had been selected to prepare Strain Hardening Cement-based Composites (SHCC), and had been researched on the influence of the factors for mechanical performance of SHCC. The results show that the presented preparation process in paper could uniformly distribute fibers in mixture. As the curing age increases, the ultimate tensile strain of SHCC appears to increase firstly and then decreases, while ultimate tensile stress shows the tendency of increase. The natural curing is beneficial for maintaining high ultimate tensile stress of SHCC, then steam curing can improve ultimate tensile stress of SHCC at early age, but ultimate tensile strain of SHCC decreases obviously as age increases. When FA/C = 1.6, 2.0, 2.4, Vf = 2.0%, and fine silica sand and natural curing were chosen, ultimate tensile strength of SHCC is up to 4MPa, and ultimate tensile strain is up to 3% at 28d.
  • NI Xin-Liang; ;;
    . 2014, 45(21): 10-0.
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    In order to improve the wettability of carbon fiber reinforced resin matrix composites (CFRP), plasma activation of CFRP surface was provided by Hall discharge plasma, and the effect of different plasma activation parameters (pressure, current and activation time) and the change of wettability of activated CFRP preserved in different conditions were learned. Many methods such as contact angle measurement, metallographic microscopic analysis and infrared spectroscopic analysis, were used to research the wettability, microstructure, and type of functional groups of the CFRP surface respectively. Research results show that the wettability of CFRP surface is improved after plasma activated with different working parameters. Infrared spectroscopic analysis indicates that the quantities of C―C and C―O bonds on the surface of activated CFRP are decreased and increased respectively. Besides, carboxyl groups, ketone groups and alcoholic hydroxyl groups are increased, while ester groups are decreased, which contributes to the remarkable improvement of wettability. Although the activated effect will reduce over time, preservation in water of room temperature can delay this reduction.
  • ;
    . 2014, 45(21): 11-0.
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    Activated carbon with large specific surface area and rich microporous structure was prepared from renewable biomass materials. It is of great significance for alleviating shortage of resources, expanding application of activated carbon in gas adsorption and EDLC. In this study, activated carbons were prepared from Hemp stem using KOH as an activator. The effects of weight ratio (KOH: straw), temperature and duration of activation on the yields and iodine adsorption values of the activated carbons were evaluated using orthogonal test design. . The micro-morphology and pore structure of activated carbons were analyzed using FE-SEM and Surface area analyzer. The results showed that weight ratio of KOH to the raw material and temperature of the activation were the most influential factors for the yield and iodine adsorption value, respectively. The optimum adsorption capability was obtained when the activation was conducted for 0.5h at 900℃ with a 4:1 weight ratio of activator to raw material. The activated carbon was obtained with a high yield of 72%,a maximum iodine value of 2047mg/g, BET specific surface area of 1924.08m2/g, total pore volume of 1.01cm3/g, average pore size of 2.1nm. The as-prepared activated carbon exhibited rich microporous structure with a microporosity of 81.19% and a narrow pore size distribution. Ultra-micropore and a high content of super-micropore were observed in the prepared activated carbon.
  • Gang Wang
    . 2014, 45(21): 12-0.
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    Fe-based amorphous alloy coating has been deposited by high velocity oxy fuel spraying. Morphology and microstructure of Fe-based alloy powders and Fe-based alloy coating have been studied by laser particle analyzer, X-Ray diffraction and scanning electron microscope. The results indicated that a coating with fully amorphous feature could be achieved using a appropriate spraying process. Furthermore, corrosion behavior of Fe-based amorphous alloy coating has been examined. The amorphous coating possesses well corrosion resistance.
  • ;
    . 2014, 45(21): 13-0.
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    (Co0.942Fe0.058)71-xSi6.4B22.6Mox (x=0~5 ) amorphous ribbons were fabricated by a single roller quenching method. The experimental results showed that with the increase of Mo amount, glass transition temperature (Tg) increases and supercooled liquid region (?Tx) reaches the maximum value of 42K with 5 at.% Mo, demonstating the addition of Mo can improve the glass forming ability. The saturation magnetization decreasing monotone with the increase of Mo amount, and with 2 at.% Mo addition the as-quenched amorphous ribbon exhibits the lowest coercive force and the highest effctive permeability. Magnetothermal treatment is effective on improving the soft magnetic properties compared with the conventional heat treatment. The saturation magnetization, effctive permeability and coercive force of the ribbon annealed in the longitudinal magnetic field increased/decreased to 80.99emu/g, 12510 and 0.64A/m. Comparing with the as-quenched state, it was increased/decreased about 40.15%, 65.52% and 48.39%, respectively. The results also showed that it was very sensitive ( 136%/(A?m-1 ) ) at a low field for the amorphous ribbon annealed in longitudinal magnetic field at a drive current frequency of 43kHz.
  • 研究 开发
  • Chang-Jing Shao;
    . 2014, 45(21): 14-0.
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    Abstract: P-doped ZnO nanocombs were successfully synthesized via a simple chemical vapor deposition (CVD) method. SEM results indicate that the production composes of nanocombs. P doping concentration is about 2 at.%. X-Ray Diffraction (XRD) spectrum of the P-doped ZnO nanocombs reflects the wurtzite structure, and no any impurity phase was detected. In addition, the photoluminescence spectra of the P-doped ZnO nanocomb were also investigated. There are three emission peaks, ultraviolet emission, green emission and near-infrared emission. The high intensity of ultraviolet and near-infrared emission peaks reveals that the crystal quality of the nanocombs is high.
  • ;; ;
    . 2014, 45(21): 16-0.
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    In this paper, a kind of Titanium-containing hydrid silicone resin was prepared by the hydrolysis-condensation of Tetra-n-butyltitanate, Methyltriethoxysilane, Dimethyldiethoxylsilane and Methylphenyldimethoxysilane through Sol-Gel method in ethanol system, using hydrochloric acid as catalyst, acetylacetone as complexing agent, hydrolysis temperature 50 ℃, and n(Ti): n(Si)=0.1~0.5. The curing condition was 140 ℃ for three days. The appearance and structure of Titanium-containing hybrid silicone resin was characterized by optical microscope, scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), ultraviolet and visible spectroscopy (UV-VIS), fourier transform infrared spectroscopy (FT-IR ) and thermal gravimetric analysis (TGA). The results indicate that, Titanium-containing hybrid silicone resin consists of Ti-O-Si covalent bond, when n(Acac)/n(Ti)=0.3, the storage stability is well, and when R/(Si+Ti)≥1.36, the resin had a smooth surface without cracks. The introduction of Ti improves its thermal property.
  • Pi-Feng YU
    . 2014, 45(21): 17-0.
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    Abstract: MnZn soft ferrite materials with NiO-CoO dopant were prepared by conventional oxide technique.The influences of CoO and NiO addition on the microstructure and magnetic properties of Low-loss and High Bs MnZn ferrites were investigated. It is confirmed that the sample with CoO addition of 0.1wt% and NiO addition of 1.28wt% ,homogeneous grains are formed and has high saturation magnetic flux density. The low loss point is located at 100℃. Valley point of power loss shifts to higher temperature with increasing of NiO dopant. With increase of CoO addition, the power losses decrease and sintering density increases. The MnZn ferrite in a specific sintering curve has excellent comprehensive properties: μi=2198 , Pcv=319 kw/m3 , Bs=451mT (T=100℃)
  • Qiong ZHANG;Sheng-Ming ZHANG;;
    . 2014, 45(21): 18-0.
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    In order to improve the molecular weight and its application on cationic dyes, trimethyl quaternary ammonium salt of lignin-sodium alginate polyampholyte (DL-SA) was prepared with trimethyl quaternary ammonium salt of lignin (DL) and sodium alginate (SA). Its structure was analyzed by FTIR, and it was investigated amphoteric polymer characteristics, ie, isoelectric point, which was found that DL and SA was grafted successfully, whose isoelectric point was 4.22 and it has compound characteristics. The effects (dosage, pH and temperature) of QL-SA on the flocculation performance of dyes were investigated with methylene blue and acid black ATT water as the representative dyes, which the removal rate of acid black ATT was 86.24% and that of methylene blue was 99.15%.It also was confirmed the optimum flocculating conditions on the two kinds of dyes and preliminary studied its flocculation mechanism.
  • ;;Heng-Feng LI
    . 2014, 45(21): 19-0.
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    Two kinds of diols with side chain, Trimethylolpropane-derived diol (TMP-derived diol) and benzyl 2,2-bis(methylol) propionate(BHP), were designed and synthesized. These two diols and commercialized GMS were mixed respectively with 4,4 '- diphenyl ether diamine (ODA) with different molar ratios as chain extenders of novel PU elastomers(PUs). The PUs were characterized by Infrared (FT-IR), thermal analysis (DSC), dynamic mechanical analysis (DMA) and the influences of the diols chain extenders on the microphase separation and damping properties of PUs were analyzed. The result show that the greater the volume of the groups on the hanging chain, the stronger the effect on the formation of Hydrogen-Bond; The Tg of the novel PUs extended by TMP-derived diol is increased,which is believed to reveal the enhanced phase mixing; In contrast, the Tg of the novel PUs extended by GMS and BHP is decreased, which indicates the enhanced phase separation; The 16 C alkyl chain and hindered phenol groups attached on hard segments can improve the Tan δ above Tg in evidence.
  • ;
    . 2014, 45(21): 20-0.
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    6H-SiC and α-Al2O3 powders that as raw materials were mixed as mass ratio of 7:3 with CaO and TiO2 as sintering additives. The green body was preoxidated for 1h at 1200℃ after being pressed.Sic matrix composites were prepared by pressureless sintering for 1 h in hydrogen atmosphere.The effects of CaO-TiO2 content and sintering temperature on the sintering properties and phase composition were investigated. The results suggested that: with the increase of sintering temperature form 1400℃ to 1500℃, the compactness improves significantly. At the sintering temperature of 1450℃,the samples were basically compact.And the sample’s apparent porosity decreased to 0.15% with w(CaO-TiO2) of 10% added. the reaction of CaO-TiO2 cristobalite、with α-Al2O3, had generated CaAl2Si2O8 at 1200℃, and generated CaTiSiO5 after 1300℃, which promote the 6H-SiC further oxidation.In the process of sintering,CaAl2Si2O8 formed liquid glass phase which deposits mullite and promoted sample’s densification.At 1500℃, the main crystal phase of the composite material is 6H-SiC, mullite.
  • LI Sheng fei
    . 2014, 45(21): 21-0.
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    Quasicontinuum method is applied to investigate the deformational mechanism of single crystal Ag thin film with Ni indenter in different crystal direction. The influences of anisotropic behavior of Ni indenter on the load necessary for first dislocation emission and contact stress distribution were studied in the nanoindentation deformation process. Results show that the sharp of the load-displacement curves are due to the collective dislocation activities. The indenter with different crystal direction can greatly influence the load necessary for first dislocation emission and contact stress distribution. The simulation results are also compared and analyzed with the Rice-Thomson dislocation model.
  • Tian-Hang Hu;Kai GUO;Jian-wei GUO
    . 2014, 45(21): 22-0.
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    This paper adopted two-step synthesis to In-situ load nano-Pt on carbon nanotube surface. Initially, we used the self-assembly effect from citric acid (CA) on aniline to prepare PANI/CNT composite support. Then, we compared two approaches as the CA coordination with H2PtCl6 precursor and without coordination, further In situ reduction for nano-Pt to achieve Pt-PANI/CNT structures. Our results showed that CA helps complete PANI wrapping for CNT surface initially, and its coordination with H2PtCl6 precursor benefits the uniform distribution and size control for nano-Pt subsequently, thus its Pt-PANI/CNT structure exhibiting high electrochemical surface area and stable methanol electro-oxidation behaviors. In this regard, we provided feasible routines to extend composite structures and their properties, helping for future explorations.
  • ;;
    . 2014, 45(21): 23-0.
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    The non-isothermal thermal decomposition process of poly(phenyltri(phenylethynyl)silane)s (PPTPES) in a nitrogen atmosphere is studied with TG-DTG technology, applying the model method combined with model-free method to get kinetic triplet and the mechanism of thermal decomposition reaction of PPTPES. The results obtained from 7 different methods show that the activation energy and the pre-exponential factor were E=252.76kJ/mol, lgA=13.93 and n=3. The reaction differential function was f(α) =1/3(1-α)[-ln(1-α)]-2 and the integral mechanism function was g(α)=[-ln (1-α)]3, and the reaction followed the random nucleation and growth mechanism.
  • ;;;;Wei Wu
    . 2014, 45(21): 24-0.
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    Monomer of SCMHBMA with 2-ureido-4[1H]-pyrimidone (UPy) group and monomer of A6ACA with alkyl group were synthesized. Novel quadruple hydrogen-bonding supramolecular network polymer was polymerized from the two monomers. The structures of monomers and polymer were characterized by infrared spectrum (IR), hydrogen nuclear magnetic resonance (1H-NMR) and mass spectrum.Thermal properties were investigated by differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA). It is proved that the product has low melting point and moderate thermal stability.The product behaves like elastomer with good toughness and mechanical properties.
  • . 2014, 45(21): 25-0.
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    Hollow carbon nanosphere (HCNS) with a microporous shell was explored to be used as electrodes for supercapacitor. The supercapacitive performances of HCNS in various kinds of neutral aqueous electrolytes (e.g., K2SO4, Li2SO4 and Na2SO4 aqueous solution) were investigated through using cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy measurements. It was found that the HCNS electrode in the neutral aqueous electrolytes showed excellent rate performance and highly efficient electrochemical accessible surface area, which was probably attributed to its unique hollow core and microporous shell nanostructure. The as-evidenced good capacitive property endowed HCNS with great application potential to carbon-based supercapacitor.
  • . 2014, 45(21): 26-0.
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    Mechano-growth factor (MGF) was found and named by Yang, generated by cells in response to mechanical stimulation, playing a key role in regulating mesenchymal stem cell (MSC) function. In this study, pre-formulated dextran glassy nanoparticles (DGNs) loaded with MGF through freezing-induced phase separation were electrospun into a polycaprolactone (PCL) copolymer fiber to secure the bioactivity of MGF, which was characterized by Field emission scanning electron microscopy(FESEM)and Transmission electron microscopy(TEM), and then bioactivity retention was certificated by the change of hMSC behaviour with confocal laser scanning microscopy and spectrophotometric microplate reader. The enhanced cell proliferation and migration show that the MGF-DGNs-loaded PCL fibrous membrane can release MGF sustainably and secure the bioactivity of MGF better than other PCL fibrous membranes, which may help find MGF-based fibrous membranes application of MSC in tissue engineering.
  • . 2014, 45(21): 27-0.
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    Abstract: The TiO2-H2O suspension was made by using the two-step method. The stability of the TiO2-H2O suspension was improved by adding the mixture of sodium dodecyl sulfate(SDS) and polyvinyl pyrrolidone(PVP). The surface tension of the solution of the two surfactants, the absorbency and Zeta potential of the suspension were measured in the case of different mass ratio of the two surfactants. Static settlement method has been used to investigate the influence of different mass ratio of the two surfactants on the stability of the suspension.The experiment results showed that the mass ratio of PVP and SDS may affect the stability of the suspension. When the mass ratio of PVP and SDS is 1:2, the improvement of the stability of TiO2 suspension is most obvious. Analysis indicates that the synergy of PVP and SDS may lead to electrostatic hindrance and space hindrance between the nanoparticles, which may be the main reason for the improvement of the suspension’s stability.
  • ; ;;;
    . 2014, 45(21): 28-0.
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    The organic-inorganic hybrid coatings based on epoxy polysiloxane resin were prepared by using three different polyetheramines (Jeffamine D230, D400, T403). The mechanical, adhesion and anti-corrosion properties were compared with the hybrid coating cured by 3-aminopropyltriethoxysilane (APTES). Compared with the hybrid coatings cured by APTES, the impact resistance property, initial adhesion and “wet adhesion” of the hybrid coatings cured by polyetheramines were promoted, comparable hardness of the hybrid coatings cured by D230 and T403 were attained, while the hardness of hybrid coating cured by D400 was decreased. The corrosion resistance behavior of the hybrid coatings was thoroughly examined by electrochemical impedance spectroscopy (EIS) and salt spray tests. It was found that the cracking and corrosion resistance of the hybrid coatings cured by APTES were improved greatly by using polyetheramines hardeners.
  • Zhi-De HU; ;;Jun-Jun GUO
    . 2014, 45(21): 29-0.
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  • Fan Shen ;;;
    . 2014, 45(21): 30-0.
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    Three diffusion of rejuvenator with different components on aged asphalt binder was contrasted by the analog diffusion test, asphalt microstructure and the molecular weight distribution was tested by Atomic Force Microscope (AFM) and Gel permeation chromatography (GPC), diffusion mechanism of different kinds of rejuvenator was analyzed. The result shows the rejuvenator’s effect gradually weakened when the diffusion depth grew, adsorbed mutual asphalt plasmodium in aged asphalt hindered the diffusion of large molecular modifying component in the asphalt, by dispersed the asphaltene the diffusion level of the modifying rejuvenator closed to that of low viscosity regeneration, the research result provides technical support to the regeneration road performance.
  • 工艺 技术
  • deng ling-feng YU Kai-ming ;;
    . 2014, 45(21): 31-0.
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    Three-dimensional LiFePO4/graphene nanostructures for lithium-ion batteries were successfully prepared by a sol-gel Sintering method. The synthesized material was characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), Transmission Electron Microscope (TEM) and a variety of electrochemical testing techniques. There were graphene sheets on the surface and among LiFePO4 Micro-nano-particles of LiFePO4/graphene composites, which indicates the Graphene and LiFePO4 of composites had be already nicely blended together. A three-dimensional conducting network of LiFePO4/graphene composites was formed by graphene sheets, which greatly enhance the electronic conductivity and reduced charge transfer resistance, thereby realizing the full potential of the active materials. The electrochemical testing indicated that the electrochemical properties of LiFePO4/graphene was better than that of LiFePO4/C. LiFePO4/graphene composite exhibited high specific capacity and superior rate performance with the discharge capacities of 163.81 mAh?g-1 at 0.1 C and 101.57 mAh?g-1 at 5 C, whereas a dis-charge capacity of LiFePO4/C is only 146.05 mAh?g-1 and 54.67 mAh?g-1 respective-ly. LiFePO4/graphene also showed an excellent cycling stability with only about 98.48% capacity retention at 0.5C rate after 100 cycles.
  • ;Guo-Wei CHEN;Yang Fei
    . 2014, 45(21): 32-0.
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    Particles of powder coating mingled poly(methyl methacrylate-ethyl acrylate) resin and kaolin as pigment were obtained in the media of supercritical carbon dioxide(sc-CO2). The effects of the EA concentration and other process factors on the copolymerization were discussed, then the powder coating was characterized by GPC, FT-IR, TG, DTGand DSC methods. The experimental results showed that the relative molecular weight of copolymer decreased and its distribution became wide with the increase of the EA monomer concentration. when the reaction temperature 75℃, reaction time 10 h, and the mass ratio of MMA/EA between 0.6/0.4 and 0.7/0.3, the molecular weight of copolymer can be reached to (4.87-5.07)×104 and its distribution was relatively narrow, which was suiable for dry surface treatment of paper. The glass-transition temperature(Tg) of the copolymer MMA/EA became lower when the increase of EA monomer concentration, therefore, an ideal glass-transition temperature of the powery coatings could be achieved by adjusting the mass ratio of MMA to EA, and the suitable Tg of MMA/EA was between 60℃ and 66℃. With the increase of kaolin, the maximum thermal degradation temperature of powder coatings increased, it made the power coating possess good film-forming property, and improve the performance of thermal-stability requirments.
  • 综述 进展
  • lan li ;
    . 2014, 45(21): 33-0.
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    PVDF based polymers are ideal matrix materials for lithium ion battery electrolyte, but high crystallinity and poor affinity to liquid electrolyte restrict their further development. In this paper, the grafting modification of PVDF based polymer electrolytes with styrene, glycidyl methacrylate, dimethyltrimethylene glycol diacrylate, polymethyl methacrylate, tripropyleneglycol diacrylate, polyethylene glycol methacrylate, 2-acrylamide-2-methyl propane sulfonic acid and polyethylene glycol by radiation, atom transfer radical polymerization and solution graft polymerization are introduced. In a certain extent, the affinity to liquid electrolyte, ionic conductivity, electrochemical stability and cycle performance have been enhanced.