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    24 January 2002, Volume 18 Issue 1
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    Articles
    Flow Injection Semi-online Preconcentration Graphite Furnace Atomic Absorption Spectrometry for Determination of Cadmium, Copper and Manganese
    ZHANG Yi-hua, WANG Mei-jia, SU Xing-guang, ZHENG Tao, ZHANG Han-qi, JIN Qin-han, CHEN Ying
    2002, 18(1):  1-7. 
    Abstract ( )   PDF (336KB) ( )  
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    A micro-flow injection sorbent extraction preconcentration system was combined with a graphite furnace atomic absorption spectrometry that formed an integrated system for the determination of trace amounts of elements. The analytical performances of the prospsed method for determining Cd, Cu and Mn were studied. The analytes were preconcentrated with a thiol resin(Type 190, produced by Nankai University, China) whose active group is -SH. The elements to be determined were preconcentrated onto the column for 60 s and then rinsed with deionized water and eluted with 30 μL of 1 mol/L HCl. The graphite furnace atomic absorption spectrometry(GFAAS) determination of the concentrated analyte was carried out in parallel with the next preconcentration cycle. Enrichment factors 41, 22 and 20 and detection limits(3σ, n=10) 0.36, 3.8 and 7.0 ng/L for Cd, Cu and Mn, respectively, along with a sampling frequency of 20 h-1, were obtained with a 60 s loading time at a sample flow rate of 3.5 mL/min. The analytical results for a number of water samples show that the flow-injection semi-online column preconcentration can not only eliminate the effect of some concomitant elements, such as Li, Na, K, Ca and Mg, on the determination of the analyte, but also enhance the sensitivity.
    pH-Sensitive Polymer Matrix with Immobilized Indicator Ion Pairs
    GUO Liang-qia, NIE Qiu-yan, XIE Zeng-hong, CHEN Yi-ting, CHEN Guo-nan, CHEN Xi, WANG Xiao-ru
    2002, 18(1):  8-11. 
    Abstract ( )   PDF (213KB) ( )  
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    A new sensor material for monitoring pH in aqueous solutions is described. It is based on lipophilic ion pairs consisting of an anionic pH indicator Bromocresol Green and a quaternary ammonium cation cetyltri-methylammonium. The ion pairs are homogeneously distributed inside the plasticized PVC membrane. The change of pH in an aqueous solution causes the change of optical property of the indicator immobilized on the plasticized PVC membrane. The plasticized PVC membrane is sensitive in a pH range from 4.0 to 6.0.
    A Chemiluminescence Optical Fiber Glucose Biosensor Based on Co-immobilizing Glucose Oxidase and Horseradish Peroxidase in a Sol-gel Film
    LI Ying-xiu, ZHU Lian-de, ZHU Guo-yi, ZHAO Chun
    2002, 18(1):  12-15. 
    Abstract ( )   PDF (643KB) ( )  
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    An optical fiber bienzyme sensor based on the luminol chemiluminescent reaction was developed and demonstrated to be sensitive to glucose. Glucose oxidase(GOD) and horseradish peroxidase(HRP) were co-immobilized by microencapsulation in a sol-gel film derived from tetraethyl orthosilicate(TEOS). The calibration plots for glucose were established by the optical fiber glucose sensor fabricated by attaching the bienzyme silica gel onto the glass window of the fiber bundle. The linear range was 0.2-2 mmol/L and the detection limit was approximately 0.12 mmol/L. The relative standard deviation was 5.3% (n=6). The proposed biosensor was applied to glucose assay in ofloxacin injection successfully.
    Chiral Separation of Ibuprofen and Terbutaline by Nonaqueous Capillary Electrophoresis with Conductance Detection
    DENG Guang-hui, WEI Shou-lian, MO Jin-yuan
    2002, 18(1):  16-19. 
    Abstract ( )   PDF (200KB) ( )  
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    In the nonaqueous N,N-dimethylformamide medium, the chiral drugs ibuprofen and terbutaline were successfully separated with sulfonyl-β-cyclodextrin(s-β-CD) as the chiral selector by capillary electrophoresis with conductance detection. The comparison of the effects of three CDS(β-CD, diethylic-β-CD, sulfonyl-β-CD) on the chiral separation was made and the resolution mechanism was proposed.
    Expression of a Hybrid Human Superoxide Dismutase with a High Affinity for Heparin
    GOU Xiao-jun, YIN Shao-man, KONG Xiang-duo, ZHU Shi-zhen, WANG Xiao-ping, ZHANG Hong-ying, ZHANG Jin, ZHU Hong, ZHAO Chun
    2002, 18(1):  20-24. 
    Abstract ( )   PDF (252KB) ( )  
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    A designed heparin-affinity of human Cu, Zn-SOD is described. The natural leader peptide of P.leiognathi Cu, Zn-SOD and a heparin-binding peptide containing a stretch of 7 Arg were fused to the N-terminal and the C-terminal of human Cu, Zn-SOD respectively. The resulted hybrid enzyme had not only a normal SOD activity but also a high affinity for heparin eluted on the heparin-Sepharose column at 0.4 mol/L NaCl. Some properties, such as the optimum pH, the thermostability and the half-life in the circulation of rats, were also analyzed.
    Thermal Decomposition Kinetics and Mechanism of Tb(Ⅲ) m-Methylbenzoate Complex with 1,10-Phenanthroline in Static Air Atmosphere
    ZHANG Jian-jun, WANG Rui-fen, ZHANG Jian-ling, WANG Shu-ping
    2002, 18(1):  25-29. 
    Abstract ( )   PDF (247KB) ( )  
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    The thermal behavior of [Tb2(m-MBA)6(phen)2](H2O)2(m-MBA=C8H7O2, methoxybenzoate; phen=C12H8N2, 1,10-phenanthroline) in static air atmosphere was investigated by means of TG-DTG and DTA methods. The thermal decomposition of the title compound takes place mainly in two steps. The intermediate and the residue for each decomposition were identified by the TG curve. By the kinetic method of processing thermal analysis data put forward by Malek et al., it is defined that the kinetics model for the first-step thermal decomposition is SB(m,n).
    Preparation of PMAA-coated Dysprosium Ferrite Ferrofluids and Study on the Superparamagnetism
    ZHU Chuan-zheng, SHEN Qin, HU Xian-luo, ZHANG Jie, ZHAO Hong
    2002, 18(1):  30-33. 
    Abstract ( )   PDF (224KB) ( )  
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    The present paper covers the unprecedented preparation of stable aqueous Dy-ferrite ferrofluids, whereby colloidal DyδFe3-δO4 ultrafine particles were dispersed by using polymeric surfactant PMAA. The stabilities of the series of the ferrofluids were studied according to the stability indexes. The susceptibility measurements were made with a Farady-type magnetic balance at various temperatures and magnetic field intensities. In terms of Langevin function, the σ versus H/T curves showed that Dy-ferrite ferrofluids exhibited superparamagnetism behavior and the blocking temperatures were in the range from 160 to 200 K. Moreover, the ferrofluids were characterized by means of Infra-red spectroscopy, transmission electron microscopy, X-ray diffraction, and Mössbauer spectroscopy.
    Fenton Reagent Generated in Electrolysis Cell and Its Usage in Degradation and Decolorization of Dyes
    CHEN Zhen, ZHENG Xi, CHEN Ri-yao, LAN Rui-fang, LIN Zhi-hong, CHEN Yu-feng, ZHANG Yi-kang
    2002, 18(1):  34-37. 
    Abstract ( )   PDF (209KB) ( )  
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    The Electro-chemistry process to produce Fenton reagents has been described. The in situ oxidation of dyes, acid chrome and alizarin red(Fenton reagents) with electrogenerated hydroxyl radicals was investigated. The I-Vcyclic voltammograms were measured. The redox peaks of the dyes were not observed in the treated dye solutions instead of a couple of O2/H2O2 redox peaks. The IR results indicate that acid chrome dye was decomposed into naphthylamine and phenol aminophenol sulfonic acid. The degradation and the decolorization of the dyes were comfirmed by the visible spectrum and the chemical analysis. The CODcr removing rate was close to 80%.
    Interatomic Potentials for NiZr Alloys from Experimental and Ab initio Calculations
    TAN Kai, LIN Meng-hai, WANG Nan-qin, ZHANG Qian-er
    2002, 18(1):  38-41. 
    Abstract ( )   PDF (405KB) ( )  
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    We applied an approach to the development of many-body interatomic potentials for NiZr alloys, gaining an improved accuracy and reliability. The functional form of the potential is that of the embedded method, but it has been improved as follows. (1) The database used for the development of the potential includes both experimental data and a large set of energies of different structures of the alloys generated by Fab initio calculations. (2) The optimum parametrization of the potential for the given database is obtained by fitting.Using this approach we developed reliable interatomic potentials for Ni and Zr. The potential accurately reproduces basic equilibrium properties of the alloys.
    ZINDO-SOS Studies on Second-order Nonlinear Optical Properties of Thiophene S,S-Dioxide Chromophores
    LIU Yong-Jun, HU Hai-Quan, ZHANG Dong-Ju, LIU Cheng-Bu
    2002, 18(1):  42-46. 
    Abstract ( )   PDF (253KB) ( )  
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    The second-order nonlinear optical properties of thiophene S,S-dioxides derivatives were studied by using the ZINDO-SOS method. The computed results show that the thiophene S,S-dioxide derivatives exhibit larger second-order polarizabilities than their thiophene precursors. In order to clarify the origin of the different NLO responses among these chromophores, their electron properties and frontier orbital properties were investigated as well. These thiophene S,S-dioxides derivatives are good candidates for their application in electro-optical device due to their high nonlinearities, good thermal and photo stabilities.
    Theoretical Investigation on the Abstraction Reaction of H with (CH3)3SiH
    ZHANG Qing-zhu, WANG Ming-gang, WANG Shao-kun, ZHANG Miao, LIU Chuan-pu, GU Yue-shu
    2002, 18(1):  47-51. 
    Abstract ( )   PDF (242KB) ( )  
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    The abstraction reaction of H with (CH3)3SiH was investigated at the high levels of ab initio molecule orbital theory. The geometries were optimized at the MP2 level with 6-31G(d) basis set, and G2MP2 level was used for the final energy calculations. The theoretical analysis provides the conclusive evidence that the main process is the hydrogen abstraction from the Si-H bond, leading to the formation of H2 and silyl radicals; the hydrogen abstraction from the C-H bond has a higher barrier and is difficult to react. The kinetics was calculated with canonical variational transition-state theory (CVT) over the temperature range 200-1 000 K, and the theoretical rate constants match well with the later experimental values.
    Structure and Mechanical Properties of Ethylene-butene Copolymers
    QUAN Da-ping, FAN Xin-gang, WANG Hai-hua
    2002, 18(1):  52-55. 
    Abstract ( )   PDF (200KB) ( )  
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    The crystallinity of ethylene-butene copolymers prepared by copolymerization of ethylene and butene in the presence of a new highly active catalyst was studied by means of DSC, WAXD and DMA. The results show that the melting temperature, the crystallinity and the crystallite size decreased with increasing the content of butene in the copolymers. The copolymers have a high degree of branching, the butene segments are mainly in the amorphous regions of the copolymers, while the polyethylene sequence forms crystal phase acting as crosslinking bondage between the molecules at room temperature. The ethylene-butene copolymers have a low modulus, a low stress and a high strain analogous to the stress-strain behavior of non-cross thermoplastic elastomer.
    Fluorescence and Photosensitizing Behavior of N-(p-Phenoxyphenyl)methacrylamide and Its Polymer
    GAO Qing-yu, LIU Zhi-gui, GUAN Hui-li, YANG Geng-xu, YU Xian-da
    2002, 18(1):  56-60. 
    Abstract ( )   PDF (254KB) ( )  
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    A novel acrylic monomer bearing aromatic ethereality group N-(p-phenoxy-phenyl) methacrylamide(MAPOA) was synthesized and polymerized. The fluorescence spectra of MAPOA and its polymer were studied, showing that the polymer displays a stronger fluorescence than its monomer at the same chromophore concentration. The fluorescence of P(MAPOA) was quenched by adding electron deficiency monomers such as MMA, AN etc.. It is another example of showing the "fluorescence structural self-quenching effect" as we reported previously, from which it is demonstrated again that this phenomenon is not an accidental one but a common effect for acrylic monomers bearing electon-donating chromophores. The photopolymerization of AN sensitized by MAPOA and P(MAPOA) was studied. The kinetic equation of the polymerization was obtained and represented as follows: Rp∝[MAPOA]0.38×[AN]0.78,Rp∝[P(MAPOA)]0.33×[AN]0.71 The overall activation energies were determined to be Ea=24.22 kJ/mol(MAPOA) and Ea=26.31 kJ/mol[P(MAPOA)] respectively. The fluorescence analysis of the resulted P(AN) showed that the sensitizer also entered into the P(AN) chains. A mechanism of the formation of a charge transfer complex and free radical initiation was suggested for the photopolymerization of AN sensitized by MAPOA and P(MAPOA).
    Preparation and Characterization of Polymeric Microspheres Having Isotactic Poly(methacrylic acid) on Their Surfaces
    CHEN Ming-qing, LIU Xiao-ya, YANG Cheng, AKASHI Mitsuru
    2002, 18(1):  61-64. 
    Abstract ( )   PDF (226KB) ( )  
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    A poly(tert-butyl methacrylate)(PBMA) macromonomer was synthesized by anionic polymerization with bis(2,6-di-t-butyl phenoxy) methyl aluminum [MeAl(ODBP)2] as the initiator and trimethylsilylmethacrylate(TMSMA) as the end capping agent in dry THF. Then, a poly(methacrylic acid)(PMAA) macromonomer was obtained by means of hydrolysis reaction from the PBMA macromonomer in the presence of hydrochloric acid. The structures of the PBMA macromonomer were characterized by using 1H NMR. It was found that the resulted PBMA macromonomer has highly isotactic properties and the PMAA macromonomer has an end vinyl group on per polymer chain. The monodisperse polymeric microspheres, which consisted of polystyrene cores and PMAA branches on their surfaces, were prepared by the dispersion copolymerization of styrene with the PMAA macromonomer in an ethanol/water mixed solvent. It was found that the concentration of the PMAA macromonomer would affect the microsphere formation, the morphology and its size in the copolymerization system.
    Green-Light Electroluminescence of Conjugated Copolymer Containing p-Phenylene-ethynylene and Oxadiazole
    YANG Mu-jie, NIU Jun-feng, HILLER Markus, LIU Xu, YE Hui, FAN Xi-zhi, CHEN Jun
    2002, 18(1):  65-69. 
    Abstract ( )   PDF (270KB) ( )  
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    The title copolymer(PDEBO) was synthesized. The thermal characteristics of the polymer were determined by means of DSC and TGA, revealing that the polymer has a good thermal stability. The X-ray diffraction measurements of the thin films showed that the polymer is disorder. Electroluminescence(EL) in the green region of the spectrum with a maximum at 500 nm was observed from the polymer films sandwiched between indium-tin-oxide and an Al electrode.
    Synthesis of Nanoscale Shell-core Titania Coated Silica Particles in the Presence of Polyether Polyamine and the Phase Transition
    HUA Feng-jun, SUN Jun, HONG Ke, GAO Lian, YANG Yu-liang
    2002, 18(1):  70-74. 
    Abstract ( )   PDF (272KB) ( )  
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    The nanoscale titania coated silica was prepared via a two-step precipitating approach, where the nanoscale silica nuclei were first prepared by passing an aqueous solution of sodium silicate through an ion-exchange resin bed, then coated with the precipitation from hydrolyzed butyl titanate in an ethanol-hexane mixture at a low pH value in the presence of poly(ethylene oxide) polyamine salt(PPA) at a high temperature of 90 ℃. In the second-step precipitating process, the spontaneously precipitated titania shell on the silica nuclei was stabilized in the suspension solution with the help of the adsorption of PPA on the particles. A possible precipitating mechanism was suggested. Furthermore, the amorphous titania shell could undergo crystallization from the amorphous to the anatase structure at a high temperature of 650 ℃, and a further phase transition from the anatase to the rutile structure in the different sintering processes at a rising temperature of 750 ℃.
    UV-Vis and Surface Photovoltage Spectra of Fe2O3/Polystyrene Composite Microspheres
    QIAN Xin-ming, ZHANG Xin-tong, SHAO Hui-bo, BAI Yu-bai, LI Tie-jin, TANG Xin-yi, DONG Shao-jun
    2002, 18(1):  75-78. 
    Abstract ( )   PDF (582KB) ( )  
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    Fe2O3 sol with the particle diameter of 3-5 nm was flocculated by the addition of SDS, and the flocculate formed was redispersed by the further addition of that surfactant. Thus the surfactant bilayer was formed on the surface of Fe2O3. The emulsion polymerization of styrene(St) adsolubilized on the surfactant adsorbed bilayer was carried out by initiator potassium persulfate(KPS). The UV-Vis and surface photovoltage spectra(SPS) indicate that the Fe2O3 particles were encapsulated in polystyrene(PSt) successfully.
    Studies on the Self-condensing Vinyl Living Radical Polymerization of a Novel Acrylate Inimer
    JIANG Bi-biao, WANG Wei-hua, YANG Yang, FU Shi-yang, FANG Xun, MIAO Chun-yu, WU Jun
    2002, 18(1):  79-83. 
    Abstract ( )   PDF (260KB) ( )  
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    A novel acrylate inimer, 2-(2-chloroacetyloxy) ethyl acrylate, was prepared by the reaction of 2-hydroxyethyl acrylate with chloroacetyl chloride in the presence of triethylamine. The self-condensing vinyl living radical polymerization of the inimer was studied and the hyperbranched macromolecules containing ester linkages on their backbone were prepared. All the polymerization products were characterized by 1H NMR. The polymerization degree and the branching parameter were calculated based on the 1H NMR spectra. It has been shown that this inimer exhibits a very distinctive polymerization behavior. Similar to step-growth polymerization, the polymerization degree of the products formed increased exponentially during the early stage of the polymerization, and then the increasing rate slowed down. However, the inimer remained present throughout the polymerization consistent with conventional free radical polymerization. Also, if much longer polymerization time was used, the polymerization system would become gel due to the crosslinking reaction derived from radical-radical recombination. As a result of the unequal reactivity of -CH2Cl and >CHCl, an almost linear product was obtained at a molar ratio of bipy to inimer=0.05, while a relatively high ratio of bipy to inimer 1 favored the formation of the branched structure. The macromolecules formed at a high ratio of bipy to inimer 1 exhibited an excellent solubility in organic solvents such as acetone.
    Hydrogen Bonding in Thermoplastic Polyurethane Elastomers: IR Thermal Analysis
    CHEN Da-jun, LI Yao-jun
    2002, 18(1):  84-87. 
    Abstract ( )   PDF (1365KB) ( )  
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    The hydrogen bond percentage and its temperature dependence of the three TPU samples synthesized from polytetrahydrofuran, 4,4'-diphenylmethane diisocyanate, N-methyl diethanol amine or 1,4-butane diol were studied by means of IR thermal analysis. The enthalpy and the entropy of the hydrogen bond dissociation were determined by the Van't Hoff plot.
    The Electroluminescence Characterization of Poly(p-phenyleneethynylene)——The π-conjugated Backbone Interrupted by a Butylene Unit
    NIU Jun-feng, YANG Mu-jie
    2002, 18(1):  88-92. 
    Abstract ( )   PDF (253KB) ( )  
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    π-Conjugated poly(p-phenyleneethynylene) with the interruption of the conjugation by a butylene unit was synthesized. Its absorption, PL and EL spectra were investigated respectively. The spectral peaks shifted to the higher energy side with the interruption of the conjugation lengths. The model compound was synthesized, by which the results were proved. The thermal characteristics of the polymer was determined by DSC and TGA, indicating that the polymer has a good thermal stability. The electroluminescence(EL) in the green region of the spectrum with a maximum at 500 nm was observed from the polymer films sandwiched between indium-tin-oxide and an Al electrode.
    Research Notes
    Synthesis of C-fused Penems By Br- or Cl-Promoted S-Heterocyclization
    SHI Hong-chang
    2002, 18(1):  93-94. 
    Abstract ( )   PDF (125KB) ( )  
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    Approaches to Pendent Groups' Functionalization of Polyimide
    FAN Hao-jun, GU Yi
    2002, 18(1):  95-102. 
    Abstract ( )   PDF (465KB) ( )  
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    Pendent groups' functionalization of polyimide is an optimum approach to improve its processability and achieve functionalized polyimide materials. There are two types of modification routes for pendent groups functionalization of polyimide: monomer route and macromolecular route. In this paper, various approaches for pendent groups' functionalization of polyimide are introduced. At the same time, a new method to achieve functional polyimide materials without decreasing its thermal stability and mechanical properties is mentioned.
Editor-in-Chief:
Jihong YU
ISSN 1005-9040
CN 22-1183/O6
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