Table of Content

10 March 2005, Volume 26 Issue 3

Previous Issue    Next Issue

Articles

Theoretical Study on Structures of EU-1 and ZSM-50 with EUO Zeo-type

LI Ji-Yang, YU Ji-Hong, XU Ru-Ren

2005, 26(3):  397-400. 

Asbtract ( )   PDF (205KB) ( )  

References | Related Articles | Metrics

Aluminosilicate zeolites EU-1 and ZSM-50 both possess the EUO framework topology which consists of 10-membered ring(MR) channels with deep side-pockets circumscribed 12-MRs. These two compounds can be synthesized in the presence of hexamethonium(HM) and diphenyldimethylammonium ions(DBDMA) as the templates, respectively. Due to the different locations of the Al sites in the frameworks of the two materials, they exhibit different molecular shape selectivity in decane isomerization. In this paper, the structures of EU-1 and ZSM-50 with EUO zeo-type are studied by using molecular dynamics simulation. Based on the calculated interaction energies of host-guest, we can successfully simulate the locations and the numbers of organic molecules in the frameworks of EU-1 and ZSM-50, the possible Si/Al ratios and the energetically favored Al sites in these two compounds. The simulated results are in good agreement with the experimental or reported data. This study also demonstrates that the importance of host-guest charge-density matching principle in the determination of structure.

Crystal Structure, Fluorescence Properties and Thermal Stability of Supra-molecule Complex [Eu(C₁₀H₉N₂O₄)(C₁₀H₈N₂O₄)(H₂O)₃]₂·phen·4H₂O

YANG Rui, HE Shui-Yang, WU Wang-Ting, SHI Qi-Zhen, WANG Da-Qi

2005, 26(3):  401-406. 

Asbtract ( )   PDF (1479KB) ( )  

References | Related Articles | Metrics

A new superamolecule complex(C₁₀H₁₀N₂O₄, H₃L=2-oxo-propionic acid salicyloyl hydrazone and C₁₂H₈N₂=1,10-phenanthroline phen) was synthesized and its crystal structure of [Eu(C₁₀H₉N₂O₄)·(C₁₀H₈N₂O₄)(H₂O)₃]₂·phen·4H₂O was determined by X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a=1.378 6(12) nm, b=1.398 8(12) nm, c=1.759 7(16) nm, α=73.977(11)°, β=68.598(12)°, γ=71.224(12)°, V=29.42(4) nm³, Z=2, μ=2.208 mm^-1, D_c=1.746 Mg/m³, F(000)=1 556, R=0.037 7, ωR=0.074 4, GOF=0.916. There are two 9-coordinated structure units in every molecule, in which Eu(Ⅲ) is coordinated by two tridentate C₁₀H₁₀N₂O₄ ligands and three water molecules and both structural units are distorted monocapped square antiprism. There are one free 1,10-phenanthrolines and four water molecules that are connected with 2-oxo-propionic acid salicyloyl hydrazone and water molecule by hydrogen bonds in the crystal cell. The complex formed a supermolecule in space through the hydrogen bonds. The composition of the complex is verified by IR, ¹H NMR and thermal decomposition. The test of luminescence capacity of the complex showed that the complex has a good fluorescence.

Preparation of Triangular Silver Nanoplates and Factors Affecting the Size and Shape of Sliver Nanoporticles

WU Qing-Song, ZHAO Yan, ZHANG Cai-Bei

2005, 26(3):  407-411. 

Asbtract ( )   PDF (747KB) ( )  

References | Related Articles | Metrics

A new non-light chemical method was reported to prepare triangular silver nanoplates. In the presence of BRIJ35 molecules, nitrate silver was reduced by sodium borohydride and sodium citrate, resulting in triangular silver nanoplates with various sizes at different temperatures. Some other factors affecting the size and shape of silver nanoplates were studied such as the concentrations of sodium borohydride and BRIJ35, the kind of surfactants, and different pH values.

Molecular Recognition of Dinuclear Salen Zinc Complex for Small Molecules with Nitrogen

ZHU Bi-Xue, RUAN Wen-Juan, GAO Feng, CAO Xiao-Hui, ZHU Zhi-Ang

2005, 26(3):  412-417. 

Asbtract ( )   PDF (617KB) ( )  

References | Related Articles | Metrics

A novel dinuclear Salen zinc complex was synthesized and characterized. The coordination number and association constants of axial coordination reaction of complex C₁₀-(Salen Zn)₂ towards imidazole, pyridine, DABCO and Pyrazine were measured by means of spectra technique. The coordination number for Im, Py and pyrazine were all 2, but for DABCO was only 1. The association constants of host-guest system decreased in the order of K0(Im)>K0(DABCO)>K0(Pyrazine)> K0(Py). The thermodynamic parameters Δ_rH_m0, Δ_rS_m0 and Δ_rG_m0 were determined. The results showed that recognition process was exothermic and entropy decrease. In addition, the studies by means of ¹H NMR and the conformations with minimal energy of the host-guest were sought by simulated annealing method, which gave the reasonable explanation for the conformation of the host C₁₀-(Salen Zn)₂ and DABCO forming complex, the spectral changes of host-guest systems were explained by quantum chemical calculations.

Synthesis and Catalytic Properties of Large Single Crystal FeAPO-5 Molecular Sieves

WEI Bo, LIU Jian-Hong, SUN Jian-Min, XIN Ming-Hong, HONG Wei-Liang, XIAO Feng-Shou, QIU Shi-Lun

2005, 26(3):  418-420. 

Asbtract ( )   PDF (476KB) ( )  

References | Related Articles | Metrics

FeAPO-5 molecular sieves large single crystals 30 μm×100 μm along a and c directions were synthesized in fluoride system by using organic amine(Et₃N) as the structure-directing agent. Its X-ray power diffraction pattern, thermal stability, scanning electron microscopy, etc. were studied. And its catalytic activity in hydroxylation of phenol with hydrogen peroxide as the oxidant was also investigated. The result shows that the phenol conversion is about 20.4% and the selectivities of catechol and hydroquinone are about 74.8% and 25.3%, respectively. It reveals that FeAPO-5 molecular sieve is a promising catalyst.

Rapid Detection of Methylmalonic Acidemia by Derivation and Electrospray Tandem Mass Spectrometry

SUN Ping, LIANG Qiong-Lin, WANG Yi-Ming, LUO Guo-An ZHANG Ting, WANG Li-Wen

2005, 26(3):  421-425. 

Asbtract ( )   PDF (620KB) ( )  

References | Related Articles | Metrics

The main biomarker of Methylmalonic acidemia was known as methylmalonic acid. Therefore, a rapid, selective and accurate method is developed to determine methymalonic acid in urine by using electrospray tandem mass spectrometry with n-butyl ester derivation and stable isotope dilution. The concentration of creatinine in urine was also determined without derivation. With this quantitative method of c(MMA)/c(creatinine), the urines samples of two MMAemia patients were analyzed through the process of treatment. The result shows that it can be used not only for the screening of inborn errors of metabolism, but also in the treatment process of MMAuria patients.

Establishment and Evaluation of Comprehensive Two-dimensional Liquid Chromatography(IEC/RP)

WANG Zhi-Cong, ZHANG Qing-He, ZHANG Wei-Bing, LI Tong, ZHAO Zhong-Yi

2005, 26(3):  426-429. 

Asbtract ( )   PDF (483KB) ( )  

References | Related Articles | Metrics

A two-dimensional liquid chromatography is established with ion-exchange chromatography(IEC) followed by reversed phase liquid chromatography(RP). The interface is a ten-port two-position switching valve coupled with two parallel RP columns. After splitting the IEC effluent with a ratio of 10:1(volume ratio), the IEC profile and the RP profile were obtained simultaneously. The system is evaluated with 5 standard proteins, which cannot be resolved in either of IEC or RP mode alone but can be resolved by the comprehensive two-dimensional liquid chromatography. The total peak capacity of this system is calculated to be 189.

Catalytic Wet Air Oxidation of Ammonia in Landfill Leachates in the Presence of Co/Bi Catalyst

LI Yu, ZHANG Rong, LI Hai-Sheng, DONG De-Ming, LIU Liang, LIU Guang-Hui, LIU Hong-Liang

2005, 26(3):  430-435. 

Asbtract ( )   PDF (1292KB) ( )  

References | Related Articles | Metrics

Catalytic Wet Air Oxidation(CWAO) was used for the decomposition of ammonia(NH₃-N) from the landfill leachates in the presence of Co/Bi catalyst and the relative content of nitrogenous organic compounds in the landfill leachates was also measured by GC-MS. The results show that the decomposition ability of NH₃-N by CWAO gradually increased with increasing reaction temperature. The kinetic decomposition of NH₃-N at temperatures 220, 240, 260 and 280 ℃ was well described with the first-order kinetics model(r>0.93, n=6). During the overall process of temperature rising(20—300 ℃), the concentration of NH₃-N increased in the first stage and then decreased in the second stage, which culminated at 220 ℃. Further investigations by GC-MS indicated that during the first stage, some nitrogenous organic compounds in the landfill leachates were degraded into NH₃-N by CWAO, and then NH₃-N was degraded by CWAO during the second stage, which presented the advantage of simultaneous removal of both NH₃-N and organic compounds by CWAO. One of the nitrogen-organic compounds, 2-mercaptobenzothiazole, in the landfill leachates was selected to verify the degradation of the nitrogen-organic compounds.

Determination of Micro Elements in Drinking Water by Using a Simultaneous MPT Spectrometer with a Flow Injection on-line Preconcentration System

JIANG Jie, FENG Guo-Dong, HUAN Yan-Fu, FEI Qiang, CAO Yan-Bo, WANG Shu-Hua, MENG Hui, JIN Qin-Han

2005, 26(3):  436-440. 

Asbtract ( )   PDF (895KB) ( )  

References | Related Articles | Metrics

A novel flow injection system with on-line preconcentration was developed for the determination of Al, Cu, Fe, Mn and Zn in drinking water by using a simultaneous microwave plasma torch atomic emission spectrometer(MPT-AES). The preconcentration column was packed with 717-anion exchange resin under alkaline conditions. The operating parameters were studied and optimized. The detection limits are 17, 0.27, 2.0, 4.3, 9.8 μg/L for Al, Cu, Fe, Mn and Zn, respectively, and the relative standard deviations are less than 5%(n=7). The new system was successfully applied to the analysis of lab-made water and tap water samples.

A Novel Regenerative Capacitive Immunosensor Based on Electrostatic Attraction for Direct Detection of the Complement Ⅲ(C₃)

WU Zai-Sheng, LI Ji-Shan, LUO Ming-Hui, SHEN Guo-Li, YU Ru-Qin

2005, 26(3):  441-445. 

Asbtract ( )   PDF (246KB) ( )  

References | Related Articles | Metrics

A regenerative capacitive immunosensor was proposed for direct detection of the complement Ⅲ(C₃) in human serum. Cysteamine selF^-assembled monolayers(SAM) firstly were combined on the gold electrode surface, and then a positively-charged chitosan monolayer was attached on the amine-modified SAM via the aid of glutaraldehyde cross-linking. To increase the insulation degree of the layer, the modified electrode was blocked with 1-dodecanethiol ethanol solution. Finally, the natural polysaccharide alginate, a negatively-charge polyelectrolyte, which was previously coupled with the anti-C₃ was adsorbed on the chitosan monolayer by strong electrostatic interaction to accomplish the immobilization of the anti-C₃. The dependence of chitosan/Au electrode stability on the pH and ion strength was studied with alternating current impedance. The immunosensor fabricated with proposed method can offer high sensitivity and easy regeneration after immunoassay through washing with basic solution without obvious decrease in response. The linear calibration curve is obtained with a detection limit of 9.1 ng/mL and a dynamic response range from 18.2 to 292.5 ng/mL when plotted vs. the logarithm of the antigen concentration. A recovery experiment demonstrates the feasibility of the proposed immunosensor for clinical diagnosis.

New Method for Preparing Core-shell Fluorescent Nanoparticles Doped with Rhodamine B Isothiocyanate

YUAN Yin, HE Xiao-Xiao, WANG Ke-Min, TAN Wei-Hong, PENG Jiao-Feng, HUANG Shan-Sheng, LIN Xia

2005, 26(3):  446-448. 

Asbtract ( )   PDF (551KB) ( )  

References | Related Articles | Metrics

In this article, the preparation of core-shell fluorescent dye nanoparticles doped with rhodamine B isothiocyanate by using novel method is reported, which involves synchronous hydrolysis of tetraethoxysilane(TEOS) in water in oil microemulsion with the combination of N-(β-amimoethyl)-γ-amino propyltriethoxy-silane(AEAPS) and rhodamine B isothiocyanate(TRITC). This method conquers the disadvantages of traditional preparation method about organic dye doped core-shell nanoparticles such as the leakage of fluorescent dyes and the low encapsulation efficiency of fluorescent dyes. The fluorescent nanoparticle prepared by using the novel method have the advantages such as high fluorescence and good fluorescent stability, which are hopeful to be applied in the field of biological labelling.

A Methylation-specific Oligonuceotide Microarray for Quantitative Analysis of p16 Gene

SHEN Jia-Yao, HOU Peng, JI Mei-Ju, LI Song, HE Nong-Yue

2005, 26(3):  449-451. 

Asbtract ( )   PDF (526KB) ( )  

References | Related Articles | Metrics

To quantitatively detect hypermethylation and to analyze methylation pattern, a methylation-specific oligonucleotide microarray for quantitative analysis was developed. The method used bisulfite-modified DNA as a template for PCR amplification, resulting in conversion of unmethylated cytosine, but not methylated cytosine, into thymine within CpG islands of interest. The amplified product, therefore, may contain a pool of DNA fragments with altered nucleotide sequences due to differential methylation status. A test sample was hybridized to a set of oligonucleotide arrays that discriminate methylated and unmethylated cytosine at specific nucleotide positions,and quantitative differences in hybridization were determined by fluorescence analysis. Four clinical samples of gastric cancer were quantitatively detected and methylation pattern of five methylated clones were analyzed with the methylation-specific oligonucleotide microarray. The results of microarray hybridization were in agreement with bisulfite genomic DNA sequencing. It showed that methylation-specific oligonucleotide microarray for quantitative analysis is a promising technique for mapping methylation changes in multiple CpG island loci and for generating epigenetic profiles in cancer.

Highly Selective Synthesis of Tetrahydropyranes by Prins-cyclization Mediated by Tin(Ⅳ) Chloride

WEN Mei-Jiao, CHANG Wei-Xing, LI Jing

2005, 26(3):  452-455. 

Asbtract ( )   PDF (617KB) ( )  

References | Related Articles | Metrics

Recently, Prins-cyclization has been widely used to synthesize tetrahydropyrane derivatives, but allyl transferring and side chain exchange will take place during the process, and the yields of the expected tetrahydropyrans were poor. In this paper, we report a new route to prepare 2,4,6-trisubstituted tetrahydropyranes with a high selectivity and excellent yields by previously coordinating aldehyde with tin(Ⅳ) chloride, then adding homo-allyl alcohol drop by drop.

Synthesis and Biological Activity of 3-Pyrimidylamino-pyrazoles

ZOU Xiao-Mao, WU Chao, ZHOU Chuan-Zheng, REN Xue-Ling, YANG Hua-Zheng

2005, 26(3):  456-460. 

Asbtract ( )   PDF (795KB) ( )  

References | Related Articles | Metrics

It has been reported that pyrazole and pyrimidine heterocyclic compounds maybe exhibit high pharmaceutical functions and pesticidal activity. A series of novel pyrimidylamino-pyrazole derivatives were synthesized and their biological activities were studied. All of the products were confirmed by ¹H NMR and elemental analysis, and some of them were characterized by IR and MS. The bioassy results indicated that some of the title compounds have a high fungicidal activity or herbicidal activity. In addition, the structure-activity relationship was discusses.

Structural Analysis of Water-soluble Polysaccharide SPA Isolated from the Stem of the Cistanche Deserticola Ma

ZHAO Wei, YAN Hong, LIANG Zhong-Yan, ZHANG Ya-Jun, JIAO Xin-Qian

2005, 26(3):  461-463. 

Asbtract ( )   PDF (450KB) ( )  

References | Related Articles | Metrics

A water-soluble crude polysaccharide was isolated from the stem of the wild Cistanche deserticola Ma. It was deproteinized by Sevage method and proteinase method, and fractionated by ultrafiltration and Sephadex G-75 column chromatography. A polysaccharide fraction SPA was collected. The polysaccharide of SPA consisted of Rha, Ara, Man, Gal and Glc in the molar ratio of 1:1.83:3.06:4.56:14.74, and the average molecular weight of SPA was around 0.76×104. By means of partial hydrolysis, Smith degradation, mathylation analysis, GC-MSIR and ¹³C NMR, the results revealed the main chain was made up of(1→6)-linked-Glc residues and substituted at 3-O. On an average, there was one branch among seven main chain residues. The side chains is composed of(1→4)-linked-Gal,(1→4)-linked-Man,(1→3)-linked-Gal and(1→2)-linked-Rha residues. The nonreduced end is composed of(1→)Ara.

3D-Quantitative Structure-activity Relationship of Insecticidal Oxime-ether Compounds Containing Sulfur(Oxygen)

LIU Ai-Ping, LU Ai-Jun, HUANG Ming-Zhi, CHEN Can, LIU Xing-Ping, LIU Zhao-Jie, YAO Jian-Ren,

2005, 26(3):  464-466. 

Asbtract ( )   PDF (753KB) ( )  

References | Related Articles | Metrics

The quantitative relationship between the structure of oxime-ether compounds containing sulfur(oxygen) and their insecticidal activity against leafhopper was studied by comparative molecular field analysis(CoMFA). The results showed that the contributions of steric and electrostatic fields to the activity were 47.5% and 52.5%, respectively. The coefficient q² of cross validation and the relation coefficient r² of non-cross validation for the model established by the study were 0.628 and 0.971, respectively, its F value was 133.840 and the standard deviation was 0.109. These values indicated that the model might have a good predictability. The contour maps of the model will give the basis on the structure modification.

Theoretical Study on Electronic Spetra and Nonlinear Optical Properties of Subphthalocyanines Substituted by NO₂ Groups

YANG Yan-Jie, SU Zhong-Min

2005, 26(3):  467-470. 

Asbtract ( )   PDF (569KB) ( )  

References | Related Articles | Metrics

Based on the geometries optimized via AM₁ method, the effects of the peripheral NO₂ group substituents of subphthalocyanine(C₂₄H₁₂B₁Cl₁N₆) on the electronic spectra and second order nonlinear optical properties were observed by using INDO/CI-SOS method. The results show that the strong electron-withdrawing groups and the increased length of conjugated chain have the less effect on the structure and the maximum absorption wavelength, but have the more effect on the second order nonlinear optical properties. With increasing of the length of conjugated chain, the β value increases much. The calculated β₀ value of the unsubstituted subphthalocyanine agrees well which the experimental result, they are -0.73×10^-28 and -0.70×10^-28 esu, respectively. The β₀ of the studied compound with the longest conjugated chain increases one order of magnitude, -1.47×10^-28 esu, in contrast to that of the unsubstituted subphthalocyanine.

Coordination Chemistry of Calix[4]arene-biscrown-6 with Cs~+ in Solution

GAO Jian-Xun, WANG Bing-Wu, ZHANG Lin, WANG Jian-Chen, SONG Chong-Li LIU Tao, HU Tian-Dou, XIE Ya-Ning, ZHANG Jing

2005, 26(3):  471-475. 

Asbtract ( )   PDF (667KB) ( )  

References | Related Articles | Metrics

The coordination chemistry of Calix[4]arene-biscrown-6(BisC₆) with Cs⁺ was studied in solution. The extraction experiments demonstrated that Cs⁺ extracting percentage at the single stage was 99.36% in o-nitrophenyl methyl ether(NPME) at room temperature. In simulated HLLW, the separation factor of Cs⁺/Na⁺ and Cs⁺/K²⁺ is 3.92×10⁴ and 2.21×10⁴ respectively. The local structure model of the complex showed that HNO₃ or H₂O might be located in the complexes. ESI-MS showed that the cesium ion complex with BisC₆ might form both 1:1 (mononuclear) and 2:1 (bisnuclear) Cs⁺: ligand species and [BisC₆·H₂O], [BisC₆·Cs⁺]⁺, [BisC₆·2Cs⁺·H₂O]²⁺, [BisC₆·2Cs⁺·NO-₃]⁺ etc. might exist in BisC₆/NPME/HNO₃ system. The EXAFS results indicated that the coordination number of cesium in BisC₆ was seven and the complex structure with seven-oxygen coordination was stable. ADF computation verified the EXAFS results.

A Thermodynamic Study on the Relationship Between Metastable Equilibrium Adsorption States and the Metastable-equilibrium Coefficient of Surface Adsorption Reactions

MA Zi-Chuan, PAN Gang, WEI Yu, CHEN Hao

2005, 26(3):  476-479. 

Asbtract ( )   PDF (902KB) ( )  

References | Related Articles | Metrics

A given metal ion can form various adsorption states with different energies on inorganic mineral surfaces under the same conditions of temperature, pressure, pH and ionic strength. For example, hydrated zinc ions were adsorbed onto manganite surfaces in two different modes of corner-linkage and edge-linkage. Surface adsorption reactions were generally terminated in various metastable equilibrium adsorption(MEA) states rather than a unique ideal equilibrium state that was predicted from the classical adsorption thermodynamics. Based on the MEA inequality of the MEA theory, we deducted the thermodynamic relationships between the real equilibrium adsorption constant(K_real) and the metastable-equilibrium coefficient(K_me). It showed that K_me is exponentially related to the energy difference between different MEA states. By affecting MEA states, kinetic factors, such as reactant concentrations, can fundamentally influence the real equilibrium adsorption constants and other thermodynamic properties such as adsorption isotherms.

Synthesis of Size-controlled Rh Nanoparticles with Liquid-phase Reduction Method and Its Application in Preparation of Hydrogen via Steam Reforming of Methanol

QIAN Ling, LV Gong-Xuan

2005, 26(3):  480-484. 

Asbtract ( )   PDF (729KB) ( )  

References | Related Articles | Metrics

Development of nanoparticles with well-defined size is an important aspect of nanotechnology. A simple method for preparing size-controlled Rh nanoparticles was developed on the basis of chemical reduction of RhCl₃·3H₂O with nitromethane. Adjusting pH of the solution is necessary in this method. Transmission electron microscopy and UV-Vis absorption were used to study the structure and behavior of the nanoparticles as a function of pH. The results show that pH value is critical determinant for the nanoparticles size in solution, in the case of pH=7, 9 and 11, the average size is 50, 30 and 13 nm, respectively, and with the increase of pH, the size of nanoparticles becomes smaller. As pH in solution is 13, the Rh nanoparticles is the smallest, with a particle size about 6 nm. The nanoparticles were supported on γ-Al₂O₃ by impregnation method. The activity for methanol steam reforming was investigated. The result indicates that the size of the nanoparticles strongly influences the activity and selectivity of steam reforming of methanol. Both conversions and selectivities are dependent on the particle size of Rh. When the nanoparticles become smaller, the activity of reactivity is improved obviously.

A New Method for Quick Determining Conformation Stability of Alanine-α-polypeptide

Wang Chang-Sheng, Wang Jia, Yang Zhong-Zhi

2005, 26(3):  485-488. 

Asbtract ( )   PDF (294KB) ( )  

References | Related Articles | Metrics

Total 23 conformers of alanine di-and tri-peptide molecules were completely optimized at B3LYP/6-31G^* level. The features of the conformer's structures were analyzed and a new method was proposed based on the density functional theory for determining the conformer's relative stability of the alanine-α-polypeptide. The parameters of the seven-membered ring O…H interaction, the five-membered ring O…H interaction, and the interaction between two special hydrogen atoms were determined from five conformers of alanine dipeptide. The 17 conformer's relative energies of the alanine tripeptide were calculated both by the new method and B3LYP/6-31G^*. Through comparing the 17 conformer's relative energies obtained by the new method and B3LYP/6-31G^*, it can be concluded that the new method and the interaction parameters are reasonable for the determination of the conformation stability of alanine polypeptides.

Theoretical Studies on Mechanism of Hydroxylation of Phenol for Producing Diphonols

CAO Wei-Liang, ZHUANG Xu-Xia, YANG Zuo-Yin, ZHANG Xin-Fang, ZHANG Jing-Chang

2005, 26(3):  489-492. 

Asbtract ( )   PDF (704KB) ( )  

References | Related Articles | Metrics

The reaction mechanism of phenol with hydrogen peroxide radical attacking its para and ortho positions in water was proposed and investigated by Density Functional Theory(DFT) method at UB3LYP/6-311G ^** UB3LYP/6-31G^* computational level. It is found that there are three transition states and three intermediate complexes along each of the reaction path, and the transition states are confirmed through frequency analysis. According to the topological analysis of molecular charge density, it is found in reaction(1), that two hydrogen bonds were formed at the IM₁ and TS₁, two ring structures(a five-membered ring and a six membered ring) were formed simultaneously. The results of the energy(including single point energy correction and the solvent effect of water) calculation show that the main activation energies of the two reactions are approximately the same, which indicates that both of the two reactions may occur. This is in accordance with the practical experiment that the catechol and hydroquinone both exist in the product mixture.

Modification of Multi-walled Carbon Nanotubes and Its Performance for Hydrogen Storage

ZHANG Xiong-Wei, CHU Wei, ZHUANG Hui-Xiang, XU Shi-Wei

2005, 26(3):  493-496. 

Asbtract ( )   PDF (620KB) ( )  

References | Related Articles | Metrics

The hydrogen storage capability of the multi-walled carbon nanotubes(MWNTs) were enhanced by chemical modifications, plasma treatment or by loading the active metals. Temperature programmed desorption(TPD) was used to test the desorption characters and calculate the mass fraction of the adsorbed hydrogen, from the peak area in TPD spectrum and the corresponding factor of hydrogen. The results showed that hydrogen storage capacities in the MWNTs increased greatly, after the chemical modification or when it was loaded with active metals. The best value in the experiments reached mass fraction 2.55%, which was seven times of that of the MWNTs without any treatment. So it was concluded that the hydrogen storage capacities in the MWNTs were improved greatly with the modifications.

Dynamics of Intercalation of B₄O₅(OH)₄^2- Anion into Layered Double Hydroxides Intercalated by Cl^- Anion

GOU Guo-Jing, MA Pei-Hua, CHU Min-Xiong

2005, 26(3):  497-502. 

Asbtract ( )   PDF (657KB) ( )  

References | Related Articles | Metrics

The dynamics feature of intercalation and assembly of B₄O₅(OH)^2-₄ into layered double hydroxides intercalated by Cl-was investigated in this paper, based on the result of monitoring for viriation of solution concentration during the reaction course, and the results of EDS, IR, XRD, TEM and TG-DTA characterization for the samples produced from different reaction course. The results testified that the displacement of Cl-accorded with Stumm's kinetics pattern, the intercalation of B₄O₅(OH)^2-₄ was controlled by diffusion course pattern. The investigation proved that the brucite layer structure and micropore structure feature of the precursor remained intact after ionic exchange, but the intercalation of bulky complicated B₄O₅(OH)^2-₄ resulted in volume expansion of unit cell in c axial, increasing of micropore specific surface area, decreasing of grain size, and varying of thermodynamic action. The lattice parameter c aggrandized from 2.399 nm to 2.558 nm, the gallery height h aggrandized from 0.322 8 nm to 0.375 6 nm, with grain size decreasing of D_a from 15.16 nm to 8.92 nm, D_c from 10.93 nm to 4.55 nm, while specific surface area increased from 92.63 m²/g to 111.20 m²/g, and the thermodynamic action and TG-DTA characteristic was altered.

Synthesis, Characterization and Catalytic Performence of La_1-xCe_xSrNiO₄(0≤x≤0.7) in NO_x Decomposition

ZHU Jun-Jiang, XIAO De-Hai, LI Jing, YANG Xiang-Guang, WU Yue

2005, 26(3):  503-506. 

Asbtract ( )   PDF (797KB) ( )  

References | Related Articles | Metrics

A series of La_1-xCe_xSrNiO₄(0≤x≤0.3) oxides were synthesized through the citric method. It was found that the content of Ce in A-site of La_1-xCe_xSrNiO₄ could reach 30%. When La was partly replaced by Ce in La_0.7Ce_0.3SrNiO₄, the catalytic activity of NO decomposition was obviously improved not only in the absence of oxygen, but also in the presence of oxygen. The activity of La_0.7Ce_0.3SrNiO₄ in NO decomposition reached 42.2%(1 123 K)in the presence of 6.0%O₂, which indicated that La_1-xCe_xSrNiO₄ was a potential catalyst for NO removal.

Studies on Gas-liquid Phase Diagram of Lennard-Jones Fluid via Particle Exchange Molecular Dynamics Simulation

OUYANG Wen-Ze, SUN Zhao-Yan, LV Zhong-Yuan, AN Li-Jia

2005, 26(3):  507-510. 

Asbtract ( )   PDF (210KB) ( )  

References | Related Articles | Metrics

A Particle Exchange Molecular Dynamics(PEMD) simulation method is proposed to study the gas-liquid phase diagram of Lennard-Jones fluid. In the simulation, two coupled boxes are adopted to represent the gas phase and the liquid phase, respectively. The equilibrium is achieved via exchanging particles between two simulation boxes only by direct comparison of their respective chemical potentials, which are calculated by using Widom method. Finally, two coupled simulation boxes possess the same temperature, pressure and particle chemical potential. The resulted gas-liquid phase diagram is in good agreement with that obtained by using other methods.

Effect of Substrate Temperature on Micro-structural Features of Zinc Perfluorophthalocyanine Thin Films

CHEN Shun-Guo, SUN Jing-Zhi, HUANG Ji, WANG Mang

2005, 26(3):  511-514. 

Asbtract ( )   PDF (637KB) ( )  

References | Related Articles | Metrics

Molecular stacking in zinc perfluorophthalocyanine(F₁₆PcZn) thin films deposited on quartz wafer at different temperatures was systematically investigated. UV-Vis absorption spectra, X-ray diffraction(XRD) patterns and atomic force microscopic(AFM) images reveal a three-step growing mechanism ranging from room temperature to 300 ℃. Firstly, a “card-packing” ground layer forms by the strong interactions between F atoms on F₁₆PcZn molecules and quartz substrate. Secondly, an “amorphous accumulation” transition layer grows on the top of the ground layer. Finally, a highly ordered “brick-stacking” crystalline layer is built up. The corresponding absorption features of these three stacking modes was shown at around 640, 670 and 810 nm respectively. The temperature-dependent variation of the feature at 810 nm indicates that the “brick-stacking” is a favorable mode at the elevated temperature. AFM images show that the F₁₆PcZn crystalline domain sizes increase with raising temperature. XRD data demonstrate that, at atmosphere temperature, the F₁₆PcZn molecules arrange in a monoclinic lattice with a constant of a=1.494 nm, while from 250 ℃ to 300 ℃, the molecular stacking evolves to a more compact mode with a little shorter constant of a=1.428 nm.

Ab initio Study on the Dipole Moments, Polarizabilities and First Hyper-polarizabilities of Fluoride-water Clusters F^-(H₂O)_n(n=1₄)

ZHANG Man, LI Ru-Jiao, WU Di, SUN Xiao-Ying, LI Zhi-Ru, SUN Chia-Chung

2005, 26(3):  515-517. 

Asbtract ( )   PDF (515KB) ( )  

References | Related Articles | Metrics

Using ab initio calculations, the optimized geometries of the F^-(H₂O)_n(n=1₄) were obtained at MP2/aug-cc-pVDZ level. The static dipole moments(μ₀), polarizabilities(α₀), anisotropy polarizabilities(Δα) and first hyperpolarizabilities(β₀) of F^-(H₂O)_n(n=1₄) were investigated with 6-311⁺⁺G(d), 6-311⁺⁺G(2d,2p) and 6-311⁺⁺G(2df,2p) basis sets at MP2 level. The relationships between above physical properties and water molecular number were discussed.

Electrolyte Optimization in Dye-sensitized Solar Cells

DAI Song-Yuan, XIAO Shang-Feng, SHI Cheng-Wu, CHEN Shuang-Hong, HUANG Yang, KONG Fan-Tai, HU Lin-Hua, PAN Xu, SUI Yi-Feng, WENG Jian, WANG Kong-Jia

2005, 26(3):  518-521. 

Asbtract ( )   PDF (180KB) ( )  

References | Related Articles | Metrics

The different electrolytes, including the solvent and solution in electrolyte, and their effect on the performance of dye-sensitized solar cells were investigated. The electrolytes were optimized according to the performance of dye-sensitized solar cells. The optimized electrolyte in dye-sensitized solar cells module was achieved, and the photon-electric conversion efficiency is 6.48% for DSCs with the size of 0.8 cm×18 cm, when ACN was used as the solvent in the electrolyte(0.1 mol/L I₂, 0.1 mol/L LiI, 0.5 mol/L TBP and 0.6 mol/L DMPII).

A Theoretical Study of UV-Vis Absorption Spectra of Heterocyclic Aromatic Polymers

FENG Dong-Dong, ZHUANG Qi-Xin, WU Ping-Ping, HAN Zhe-Wen

2005, 26(3):  522-526. 

Asbtract ( )   PDF (640KB) ( )  

References | Related Articles | Metrics

The UV-Vis absorption spectra of some heterocyclic aromatic polymers were investigated with a combined theoretical and experimental approach. Geometry optimizations are performed with the semiempirical Austin Model(AM₁) on PBZ(polybenzazole) oligomers with increasing chain length. Then the optical absorption spectra are simulated theoretically by using Zerner's intermediate neglect of differential overlap method(ZINDO), coupled to single configuration interaction(CI). The corresponding experimental spectra are recorded in MSA solution. The comparison of the observed and the calculated absorption spectra of PBZ show a deviation due to the effect of environment.

Direct Gas Phase Synthesis of Propylene Oxide Using Propylene-Oxygen Plasma

GUO Ming-Xing, GUO Hong-Chen, WANG Xiang-Sheng, ZHOU Jun-Cheng, ZHAO Jian-Li, CHEN Li-Xing, GONG Wei-Min

2005, 26(3):  527-530. 

Asbtract ( )   PDF (497KB) ( )  

References | Related Articles | Metrics

The role of plasma activation in the direct gas phase epoxidation of propylene with molecular oxygen is discussed for the first time. The plasma was obtained by applying pulse corona discharge to the mixture of oxygen and propylene at room temperature and atmospheric pressure by using a needle-plate reactor. The reaction mixture was analyzed by an on-line chromatography. The effects of some main parameters on propylene conversion, PO yield and PO selectivity, such as the space between the electrodes, the pulse discharge frequency as well as the pulse discharge voltage, were investigated. It is observed that, at room temperature and atmospheric pressure, propylene and oxygen can be directly converted into PO in gas phase only by plasma activation. The proper adjustment of above parameters can rise the yield of PO. When the pulse voltage of corona discharge is fixed at 18 kV, the yield of PO, the conversion of propylene and the selectivity of PO are 5.15%, 19.15% and 26.89%, respectively.

Influence of Sub-layer on SelF^-humidifying Performance of PEMFC

WANG Cheng, MAO Zong-Qiang, XU Jing-Ming, XIE Xiao-Feng, YANG Li-Zhai

2005, 26(3):  531-534. 

Asbtract ( )   PDF (567KB) ( )  

References | Related Articles | Metrics

To research the effect of sub-layer on selF^-humidifying performance of PEMFC, the membrane electrode assemblies with different PTFE contents and different loading amount of PTFE/C mixture in sub-layer were prepared, and then single PEMFCs were assembled for experimental studies of polarization and AC impedance. The results indicated that the peak power density of H₂/O₂ PEMFC was improved about 0.1 W/cm² when PTFE content in sub-layer increased from 24% to 35%, but its peak power density decreased with PTFE content up to 42%. However, the selF^-humidifying performance of H₂/air PEMFC increased all along. The loading amount of sub-layer had an important influence on selF^-humidifying performance of PEMFC, the peak power density of H₂/O₂ PEMFC was improved about 0.27 W/cm² when sub-layer loading amount increased from 0 to 4.0 mg/cm². Finally, the microstructures of the sub-layer were analyzed by the methods of intrusion Hg measurement and SEM.

SiO₂ Colloidal Crystals and Macroporous Materials Using Them as Template

CONG Hai-Lin, CAO Wei-Xiao

2005, 26(3):  535-539. 

Asbtract ( )   PDF (790KB) ( )  

References | Related Articles | Metrics

A series of monodispersed silica spheres with the diameter from 35 to 750 nm was successfully synthesized by using the Stober method under different conditions, and the corresponding colloidal crystals were fabricated and investigated. UV-Vis reflectance spectra show that the wavelength of reflection spectra of the silica colloidal crystals accords well with those calculated from Bragg Law. The macroporous SiO₂ and diazoresin(DR) were prepared respectively by using the polymeric and SiO₂ monodispesed spheres as the template.

Theoretical Studies on N-Phosphorylized Amino Acids Properties by Quantum Chemical Calculation

DU Jin-Tang, LI Yan-Mei, CHEN Zhong-Zhou, TAN Bo, JIANG Yang, ZHONG Ru-Gang, ZHAO Yu-Fen

2005, 26(3):  540-545. 

Asbtract ( )   PDF (607KB) ( )  

References | Related Articles | Metrics

Some interesting phenomena such as peptide formation, ester formation, ester exchange on phosphorus and N→O migration occur at room temperature when the amino group of amino acid is associated with phosphoryl group. In this paper, quantum chemical calculation was used to discuss these reaction mechanisms. It is found that MNDO method is one of the best semiempirical method to be used in the calculation of penta-coordinate phosphoric intermediates qualitatively. Therefore, it can be used widely in the study of phosphorus chemistry. In ab initio and density functional calculations, the model in which isopropyl group on phosphorus atom is simplified by methyl group was reasonable. It was found that the stabilities of the penta-coordinate intermediates and transition states were affected by the strain energies, charges, hydrogen bond and steric hindrance. The penta-coordinate phosphoric intermediates with five-membered ring from α-carboxylic groups were the most stable, and then are those with six-membered ring from β-COOH, while those with seven-membered ring from γ-carboxylic groups were the most unstable. The energies of the corresponding transition states showed the same relative stability pattern. Meanwhile, the intermediates with six-membered or seven-membered ring in di-equatorial spanning arrangements are highly unstable than those in apical-equatorial spanning arrangements. The calculation results can be used to explain the facts that why N-phosphoryl amino acids with a polar side chain have higher activities. The energies of the transition states in gas phase and solutions showed that the peptide formation from α-COOH could take place in aqueous solution without any coupling reagents under a mild condition. Meanwhile, β-COOH and γ-COOH could not be involved in the reaction because of their high activation energies. Therefore, the calculation results and the experiments show that only α-COOH is selected to form peptides by N-phosphorylation under mild conditions. These might give some clue to the study on the origin of proteins, protein biosynthesis, and combinational peptide synthesis, and might help explain why nature chose α-amino acids as the protein backbone.

Pharmacophore Models and 3D-QSAR Studies of Rat and Fly's GABA Receptor Inhibitors

REN Tian-Rui, SHEN Bin, PEI Jian-Feng, WANG Yong-Sheng, XIANG Wen-Sheng

2005, 26(3):  546-549. 

Asbtract ( )   PDF (579KB) ( )  

References | Related Articles | Metrics

Aminobutyric acid(GABA) plays an important role as a major inhibitory neurotransmitter in both vertebrates and invertebrates, which have similar but pharmacologically distinct GABA_A receptors, so insect's GABA_A receptors are regarded as a promising target for insecticides. In this paper, two pharmacophore models of rat and fly's GABA_A receptors for a series of reported inhibitors were studied by DISCOtech methodology, which laid a foundation for finding the leading compounds and designing new selective compounds. According to this study, the three-dimensional quantitative structure and activity relationships were studied, which gave two predictive CoMFA models with q_rat²= 0.526 and q_fly²=0.679. The CoMFA models verified the pharmacophore models, and gave insights to the design of better GABA_A receptor inhibitors.

Biomimetic Modification of Phosphonized Chitosan Membrane

ZHANG Min, CUI Jun-Feng, YIN Yu-Ji, YAO Kang-De

2005, 26(3):  550-553. 

Asbtract ( )   PDF (671KB) ( )  

References | Related Articles | Metrics

Biomimetic growth of calcium phosphate over chitosan might be an effective approach to constitute inorganic/organic composite biomaterial. In this study, N-methylene phosphonic chitosan(NPCS) was synthesized via formaldehyde addition and condensation with phosphoric acid in a step reaction. The NPCS obtained was characterized by FTIR, XPS and ICP analyses. A stimulated body fluid was used to deposit hydroxyapatite(HA) on the surfaces of NPCS film. SEM and water contact angle measurement were performed to evaluate the surface texture and hydrophilicity of the materials. The data of XRD and EDX demonstrated that HA layer deposited on NPCS film surface in a SBF, has a low crystallinity with n(Ca)/n(P) being nearly 1.60 when immersing time extended for 20 days.

Preparation and Characterization of Biodegradable Insulin-loaded Microspheres

ZHANG Xue-Fei, HU Jun-Li, CHEN Xue-Si, JING Xia-Bin

2005, 26(3):  554-557. 

Asbtract ( )   PDF (577KB) ( )  

References | Related Articles | Metrics

Insulin-loaded microspheres were prepared by solid-in-oil-in-water(S/O/W) technique with a polymer alloy of poly(lactic acid-co-glycolic acid)(PLGA) and monomethoxy polyethylene glycol-b-polylactic acid(MPEG-PLA) as the carrier material. It was demonstrated that the microspheres prepared by the S/O/W technique contain more insulin than those prepared by water-in-oil-in-water(W/O/W). They had a spherical shape. Their mean size was in the range of 1—3 μm. Their cross-section had a core-shell structure and the insulin located in the core of the capsule as a crystal solid. The shell itself was layered due to the phase-separation of the polymer alloy during the course of solvent evaporation. The in vitro release behavior of the insulin mirospheres prepared by S/O/W and by W/O/W were compared. It was found that less initial burst release of insulin from the mirospheres prepared by S/O/W was observed than the other. This improvement in initial burst release was dependent on the ratio of the two components of the polymer alloy.

Synthesis, Characterization and Properties of New Soluble Phthalazinone Moiety-based Aromatic Poly(aryl amide)s Containing Chlorine Substituents

LIU Cheng, LIU Peng-Tao, WANG Jin-Yan, WU Chun-Rui, WANG Pei, JIAN Xi-Gao

2005, 26(3):  558-561. 

Asbtract ( )   PDF (572KB) ( )  

References | Related Articles | Metrics

A new chloro-substituted phthalazinone unit-containing aromatic diacid, 4-[3-chloro-4-(4-carboxy phenoxy)phenyl]-2-(4-carboxy phenyl)phthalazin-1-one(Ⅲ), was derived from the nucleophilic substitution of p-chlorobenzonitrile with the bisphenol-like monomer, 4-(3-chloro-4-hydroxy-phenyl)-2H-phthalazin-1-one(Ⅰ), followed by alkaline hydrolysis of the intermediate dinitrile, 4-[3-chloro-4-(4-cyano phenoxy)phenyl]-2-(4-cyano phenyl)phthalazin-1-one(Ⅱ). The structure of diacid Ⅲ was confirmed by FTIR, ¹H NMR, ¹³C NMR and MS. Moreover, ¹H and ¹³C NMR spectra of diacid Ⅲ were completely assigned by the two-dimensional NMR, such as gCOSY, gHMBC and gHSQC spectra. Using triphenyl phosphate(TPP) and pyridine as the condensing agents, a series of poly(aryl amide)s with inherent viscosities in the mass concentration range of 0.38—1.23 dL/g were prepared by the direct polycondensation of diacid Ⅲ with various aromatic diamines. Thus, the twisted, non-coplanar and unsymmetrical phthalazinone moieties were successfully introduced into the polymer main chain by the polycondensation method. All the poly(aryl amide)s containing chloro-substituted phthalazinone moieties were amorphous in nature, as evidenced by X-ray diffraction. Most of the poly(aryl amide)s were quite soluble in a variety of organic solvents, such as N-methyl-2-pyrrolidone(NMP), N,N-dimethylacetamide(DMAc), N,N-dimethylformamide(DMF) and dimethylsulfoxide(DMSO), and even in pyridine and m-cresol. All the resultant poly(aryl amide)s could be cast into transparent and tough films, indicating the feasibility of processing for application. The glass-transition temperatures of the polymers were determined by DSC method and they were in the temperature range of 291—332 ℃. These poly(aryl amide)s had useful levels of thermal stability associated with 10% mass-loss in excess of 460 ℃ in nitrogen, determined by TGA.

Synthesis, Structure and Nonlinear Optical Properties of Two-photon Photopolymerization Initiator BVPDA

YAN Yun-Xing, TAO Xu-Tang, XU Gui-Bao, YU Wen-Tao, YANG Jia-Xiang, WU Yong-Zhong, YU Xiao-Qiang, ZHAO Xian, JIANG Min-Hua

2005, 26(3):  562-566. 

Asbtract ( )   PDF (918KB) ( )  

References | Related Articles | Metrics

A new two-photon photopolymerization initiator {4-[2-(4-bromophenyl)vinyl]phenyl}-diphenyl-amine(BVPDA) was synthesized and characterized by ¹H NMR, ¹³C NMR and elemental analyses. The crystal structure was characterized by X-ray diffraction structural analyses. BVPDA belongs to the triclinic space group P1 with a=1.083 4(3) nm, b=1.562 5(2) nm, c=1.964 0(2) nm, α=92.807(8)°, β=103.647(10)°, γ=106.676(13)°, V=3.070 5(10) nm³, Z=6, T=293(2) K, D_c=1.383 g/cm³, R₁=0.073 5 and wR=0.106 3. The linear absorption, one-photon fluorescence, one-photon fluorescence lifetime and two-photon fluorescence are experimentally studied. When pumped with 760 nm laser irradiation, BVPDA indicates a strong two-photon induced fluorescence of 462 nm. A microstructure using BVPDA as the initiator was fabricated using BVPDA as the initiator under irradiation of 200 fs, 76 MHz Ti:sapphire femtosecond laser at 760 nm.

A Novel Hydrophilic Organo-inorganic Pervaporation Separation Membrane ——Preparation of Polyacrylamide Composits Membrane

ZHOU Li-Zhi, WANG Xing, CHENG Xiao-Wei, LONG Ying-Cai, PING Zheng-Hua

2005, 26(3):  567-570. 

Asbtract ( )   PDF (834KB) ( )  

References | Related Articles | Metrics

A novel hydrophilic organo-inorganic composite membrane was prepared by graft-polymerization of acrylamide on a microporous silica membrane, preliminary silylated by γ-(methyl acryloyl) propyl tri-methoxysilane. The surface properties and morphology of the membrane were analyzed by means of SEM, AFM, FTIR and TGA. The influence of monomer concentration on membrane performances for dehydration of ethanol was systematically studied. It was found that the membrane was very selective and permeable for dehydration of alcohol and acrylic acid. The membrane grafted in 3% of AM has good separation performances. The influence of feed concentration and operation temperature on membrane permeation is special.

Synthesis of Tetramethylcyclopentadienyl-phenoxytitanium Dichlorides and Their Catalytic Properties for Ethylene Polymerization

ZHANG Yue-Tao, MU Ying, LV Chun-Sheng, ZHANG Fan, CHEN Cong-Xi

2005, 26(3):  571-574. 

Asbtract ( )   PDF (210KB) ( )  

References | Related Articles | Metrics

Four constrained geometry tetramethylcyclopentadienyl-phenoxytitanium dichlorides 4-R₁-6-R-2-Me₄Cp-PhOTiCl₂[R₁= ^tBu, R= ^tBu(5); R₁=H, R= ^tBu(6), Ph(7), Me(8)] were successfully prepared from the reaction of TiCl₄ with the corresponding trimethylsilyl-functionalized ligands, which was obtained by treating the ligands 4-R₁-6-R-2-Me₄CpH-PhOH[R₁= ^tBu, R= ^tBu(1); R₁=H, R= ^tBu(2), Ph(3), Me(4)] with nBuLi and Me₃SiCl subsequently. The yields are higher than those previously reported. When activated with iBu₃Al and Ph₃C⁺B(C₆F₅)-₄, complexes 5—8 exhibit a reasonable catalytic activity for ethylene polymerization, producing ethyl branched polyethylenes. Influences of the molecular structure of these complexes and polymerization conditions on their catalytic properties were studied. Polyethylenes obtained with these catalysts were characterized.

Synthesis of Fluorinated Acrylate Ternary Copolymer Latex by Miniemulsion Polymerization and Characterization

ZHANG Qing-Hua, ZHAN Xiao-Li, CHEN Feng-Qiu

2005, 26(3):  575-579. 

Asbtract ( )   PDF (688KB) ( )  

References | Related Articles | Metrics

Stable fluoroacrylate copolymer emulsion in the size range of 110—150 nm was made by miniemulsion polymerization under employment of low dose of emulsifiers and no coemulsifiers, with fluoroacrylate(FA), butyl methylacrylate(BMA), methyl methyl-acrylate(MMA) as the monomers. The molecular weight and composition of copolymer were demonstrated by GPC, FTIR and ¹H NMR, the change of latex partical sizer in the polymerization process was determined, and the surface property of films was studied by Wilhelmy method. It is shown that mixed monomer species allows efficient copolymerization to occur, and products with a high conversion of fluoromonomer(95%) and narrow molecular weight distribution(1.3—1.5) were obtained, and the polymer particles were found to be one-to-one copy of the monomer droplets and drop nucleation was the dominant mechanism in the polymerization process, some properties of fluoroacrylate copolymer latex of miniemulsion were improved, the excellent water and oil repellency of the copolymer film without coemulsifiers influence were preserved while the amount of fluorinated compounds required in the polymer is reduced considerably.

Dynamic Mechanical Properties of Controllable Cross-linking Poly(ether ether ketone)s

LIU Xin-Cai, ZHOU Hong-Wei, LI Zhi-Cheng, CHEN Chun-Hai, WEI Zhan-Hai, ZHANG Wan-Jin

2005, 26(3):  580-582. 

Asbtract ( )   PDF (341KB) ( )  

References | Related Articles | Metrics

Dynamic mechanical analysis(DMA) was used to investigate the dynamic mechanical and thermal properties of the controllable cross-linking poly(ether ether ketone)s containing thioether bond and pure poly(ether ether ketone). The processes of cross-linking reaction were monitored with the changes in storage modulus(E') and tanδ with the change of temperature. The storage modulus(E') increases in the high temperature region and tanδ shifts toward high temperature with increasing the degree of cross-linking. Comparing dynamic mechanical properties of pure poly(ether ether ketone) with that of the controllable cross-linking poly(ether ether ketone)s, we can conclude that the cross-linking reaction could occurred at the sites of thioether bonds. The novel polymer can be processed as conveniently as thermoplastic material before cross-linking and has a high application temperature as thermosetting material after cross-linking. It can be applied to a new technological region.

Confined Crystallization of Poly(vinylcyclohexane)-b-poly(ethylene)-b-poly(vinylcyclohexane) Triblock Copolymer in Solution

YU Pei-Qian, LI Hong-Sheng, WANG Zhen, XIE Xu-Ming, Bates Frank S.

2005, 26(3):  583-585. 

Asbtract ( )   PDF (562KB) ( )  

References | Related Articles | Metrics

The crystallization of poly(vinylcyclohexane)-b-poly(ethylene)-b-poly(vinylcyclohexane)(PVCH-PE-PVCH) triblock copolymer/chloroform solution was investigated. The solvent of the solution system was evaporated at various temperatures. It was found that the crystallinity was decreased with increasing the solvent evaporating temperature. This indicated that the crystallinity depends on the crystallization time because the higher the evaporating temperature, the faster the speed of the solvent evaporating is. However, the melting temperature(T_m) of the block copolymer was found to depend on the competition between the crystallization and the microphase separation. When the evaporating temperature is lower(below 333 K), i.e. the speed of the solvent-evaporating is slow, the PE block crystallized freely and the T_m increased with increasing the solvent evaporating temperature, implying that the T_m only depends on the crystalline temperature. On the other hand, with the increasing temperature up to above 343 K for solvent evaporating, two melting peaks at 356 and 377 K were observed for the crystallization of PVCH-PE-PVCH in the solution. It resulted in that the crystallization and the microphase separation of the block copolymer occurred simultaneously. And the confined and unconfined crystallization coexisted for the samples. The competition of the crystallization and the microphase separation can be controlled through changing the solvent evaporating speed.

Synthesis and Properties of a Novel Kind of PEAK(Poly Aryl Ether Ketone) with Lower Dielectric Constant

WANG Yang, MU Jian-Xin, ZHU Cun-Sheng, JIANG Zhen-Hua

2005, 26(3):  586-588. 

Asbtract ( )   PDF (457KB) ( )  

References | Related Articles | Metrics

A novel monomer [2-(4-phenoxyphenyl)-1,4-diphenol] was synthesized. A novel polymer(4-phenoxyphenyl)PAEK was successfully synthesized with this new type of diphenol and 4,4'-difluorobenzophenone in TMSO. The ¹H NMR and IR characterizations of the monomer and polymer were described. Some properties of the polymer were also given out. It keeps good properties of PEEK(poly ether ether ketone)(Tg is 407 K and TGA plot shows that the weight loss of the monomer is 5% at 320 ℃ and 10% at 347 ℃) and also has better solubility, lower dielectric constant 2.9 at 1 MHz and lower dielectric loss 4.49×10^-3 at 1MHz. This kind of novel non-fluorinated PAEK(poly aryl ether ketone) with anisomerous big side group is very promising for electronic applications

Synthesis and Characterization of Block Copolymers Containg Poly(aryl ether ketone) and Liquid Crystalline Polyester Segments

YANG Yan-Hua, DAI Xiao-Hui, ZHOU Bing, MA Rong-Tang, JIANG Zhen-Hua

2005, 26(3):  589-591. 

Asbtract ( )   PDF (443KB) ( )  

References | Related Articles | Metrics

Block copolymers containing poly(aryl ether ketone) unit and different lengths of thermotropic liquid crystalline polyesters(TLCP) segments were synthesized by high temperature solution polymerization. The chemical structure, thermal properties and liquid crystalline behavior of the block copolymers were investigated by FTIR, DSC and PLM respectively. A single glass transition revealed that the two blocks had good a compatibility. The length of TLCP segment had a significant influence on the copolymer's liquid crystalline behavior. When the molecular weight of TLCP reduced to 2965, liquid crystallinity of copolymer disappeared. The block copolymers showed a typical nematic threaded texture which differed from polyester's.

Synthesis and Chain-extending Effect of Bis(N-methyl-acetamido) dimethylsilane

HU Hong-Guo, ZHENG Qiang, LIN Wei-Wei, CHEN Chun-Rong, TAO Xiao-Le

2005, 26(3):  592-594. 

Asbtract ( )   PDF (370KB) ( )  

References | Related Articles | Metrics

A linear difunctional silylamide, bis(N-methylacetamido)dimethylsilane(MADMS), was synthesized by the reaction of dimethyldichlorosilane and N-methylacetamide. The chemical structure of the product was confirmed by IR, ¹H NMR and elemental analysis. When MADMS was mixed with PDMS, both the molecular weight and the viscosity of the mixture, as measured by GPC and viscometer, were found to be increased significantly in the initial period, which was ascribed to the hydrolysis efficiency of MADMS. The results show that MADMS possessed the chain-extending ability and can be used for mass application.