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A HYBRID POLYMER GEL AND ITS STATIC NONERGODICITY

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Chinese Journal of Polymer Science 2002年第3期20卷 269-274页

作者： Yue Zhao Chi Wu The Open Laboratory of Bond Selective chemistry department of Chemical Physics, University of Science and Technology of china Hefei 230026 china department of chemistry The Chinese University of Hong Kong Shatin, N.T., Hong Kong china Univ Sci & Technol china Dept Phys Chem Open Lab Bond Select Chem Hefei 230026 Peoples R China Chinese Univ Hong Kong Dept Chem Shatin Hong Kong Peoples R China

We used a thermally reversible hybrid gel made of billions of physically jam-packed swollen thermally sensitivepoly(N-isopropyl-acrylamide) chemical microgels. Laser light scattering study on a series of such hybrid gels formed atdifferent gelling rates and temperatures revealed that the position-dependence of the scattering speckle pattern(staticnonergodicity) came from large voids formed during the sol-gel transition. With a proper preparation, such a nonergodicitycould be completely removed, indicating that the static nonergodicity generally observed in a gel is not indinsic, but comesfrom the clustering "island" structure formed during the gelation process.

关键词： Polymer gel Nonergodicity Dynamic light scattering

PROPERTIES AND SYNTHESIS OF NEW SUPPORTS FOR IMMOBILIZATION OF ENZYMES BY COPOLYMERIZATION OF VINYLENE CARBONATE AND METHACRYLIC ACID

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Chinese Journal of Polymer Science 2000年第4期18卷 343-349页

作者： Lun-han Ding Yue Li Yan Jiang Zhe Cao Jia-xian Huang department of Polymer Science and Engineering, University of Science and Technology of china, Hefei 230026, china department of chemistry, Nankai University, Tianjin 300071, china Univ Sci & Technol china Dept Polymer Sci & Engn Hefei 230026 Peoples R China Nankai Univ Dept Chem Tianjin 300071 Peoples R China

Methacrylic acid first was neutralized with an aqueous solution of NaOH to pH = 6.0 similar to 7.0, vinylene carbonate (VCA) was added to the solution, then monomers were copolymerized in paraffin oil by means of reverse-phase suspension polymerization and hydrophilic copolymeric supports were prepared. The properties of the supports were determined using trypsin and results show that the amount of enzymes coupled to the supports and the specific activity of immobilized trypsin are related to the content of VCA structure units, reaction time and concentration of enzyme solution, etc.

关键词： vinylene carbonate methacrylic acid fixed enzyme support trypsin

Performance of Hyperspherical Harmonic Expansionon the Low-lying P and D States of Helium Atom

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Chemical Research in Chinese Universities 2000年第4期16卷 351-355页

作者： WANG Yi-xuan, ZHUANG Bing-you and LIU Cheng-bu (School of chemistry, Shandong University, Jinan 250100, china) (department of chemistry, Weifang College, Weifang 261043, china) Shandong Univ Sch Chem Jinan 250100 Peoples R China Weifang Coll Dept Chem Weifang 261043 Peoples R China

The wave functions of the n1,3p (n=2, 3, 4) and the n 1,3D (n=3, 4, 5 ) low-lying states of the helium atom are expanded into the complete sets of the symmetrically adapted basis functions from hyperspherical harmonic functions in the angle part and of generalized Laguerre functions in the radial part respectively, and are then augmented by the simplest type of Jastrow correlation factor to incorporate electron-nucleus cusp only. The excellent agreement between the present nonrelativistic eigen-energies and those from the sophisticated configuration interaction (CI) method for the examined states indicates that the hyperspherical harmonic method can also be applied to the P and the D excited states of the helium atom.

关键词： Hyperspherical coordinate Helium atom Excited state

THE VISCOELASTIC EFFECT ON THE FORMATION OF MESO-GLOBULAR PHASE OF DILUTE HETEROPOLYMER SOLUTIONS

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Chinese Journal of Polymer Science 2003年第2期21卷 117-122页

作者： Chi Wu The Open Laboratory of Bond Selective chemistry department of Chemical Physics, University of Science and Technology of china, Hefei 230026 china department of chemistry The Chinese University of Hong Kong Shatin, Hong Kong Univ Sci & Technol china Dept Chem Phys Open Lab Bond Select Chem Anhua 230026 Peoples R China Chinese Univ Hong Kong Dept Chem Sha Tin Hong Kong Peoples R China

Linear homopolymer chains in poor solvent exist either as individual crumpled single chain globules or asmacroscopic precipitate, depending on whether the solution is in the one- or the two-phase region. However, linearheteropolymer chains in dilute solution might be able to form stable mesoglobules made up of a limited number of chains ifthe degree of amphiphilicity of the chain is sufficiently high and the experimental conditions are appropriate. The self-assembly of block copolymers in a selective solvent is typical of such examples. In practice, the formation of stablemesoglobules can be directly related to the formation of novel polymeric nanopaticles in solution. In this article, we willaddress the formaton of mesoglobular phase not only on the basis of thermodynamics, but also from a kinetic point of view,which leads to the discussion of how viscoelasticity can affect the phase behavior of heteropolymer chains in dilute *** formation and stabilization of several different kinds of novel polymeric nanopedicles will be used to illustrate ourdiscussion.

关键词： Viscoelasticity Mesoglobular phase Heteropolymer Nanoparticle Polymer Dispersion Microphase inversion

Oxyfunctionalization of ketones bearing α-methylene group with piperidine oxoammonium *** of α-diketones from monoketones

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Chinese Journal of chemistry 1996年第3期14卷 252-258页

作者： LIU, You-Cheng REN, Tan GUO, Qing-Xiang National Laboratory of Applied Organic chemistry, Lanzhou University,Lanzhou, Gansu 730000, china department of Modern chemistry, University of Science and Technology of china,Hefei, Anhui 230026, china National Laboratory of Applied Organic chemistry Lanzhou University Lanzhou Gansu 730000 China department of Modern chemistry University of Science and Technology of China Hefei Anhui 230026 China National Laboratory of Applied Organic chemistry Lanzhou University Lanzhou Gansu 730000 China National Laboratory of Applied Organic chemistry Lanzhou University Lanzhou Gansu 730000 China department of Modern chemistry University of Science and Technology of China Hefei Anhui 230026 China [*]Address correspondence to this author at University of Science and Technology of china.

A facile method for the title transformation is described. The reaction of 2,2,6,6-tetramethyl-4-methoxypiperidine oxoammonium chloride (1b) and ketones bearing a-methylene group in acetonitrile proceeded smoothly to give the a-oxyfunctionalized coupling products (6a-h). These coupling products decomposed upon heating in acidic medium to produce a-diketones (7a-h) in good to excellent yields.

关键词： Piperidine oxoammonium salt monoketones,α-diketones synthesis

POLYMERIZATION OF ETHYLENE METHYL PHOSPHATE IN THE PRESENCE OF SODIUM POLY(ETHYLENE GLYCOL)ATE

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Chinese Journal of Polymer Science 1999年第3期17卷 259-264页

作者： Jie Wen Ren-xi Zhuo Lu Wang Laboratory of Biomedical Materials of the State te Education Commission of china, department of chemistry, Wuhan University, Wuhan 430072, china Wuhan Univ Dept Chem State Educ Commiss China Lab Biomed Mat Wuhan 430072 Peoples R China

Poly(ethylene methyl phosphate)-poly(ethylene glycol)-poly(ethylene methyl phosphate) triblock copolymers carrying hydroxyl group at both chain ends were synthesized with sodium poly(ethylene glycol)ate as initiator. The effects of the factors such as solvent, amount of the initiator and reaction time were investigated. The copolymers were characterized by IR, H-1-NMR, H-1{P-31}-NMR, C-13-NMR, P-31{H-1}-NMR, and DSC. High molecular weight of the copolymer and high yield of the polymerization were achieved within 3 min at 25 degrees C. The polymerization process was studied by P-31{H-1}-NMR and transesterification was found during longer polymerization time.

关键词： ethylene methyl phosphate sodium poly(ethylene glycol)ate telechelic polymer block copolymer

IR STUDY ON MONOMOLECULAR PARTICLE AGGLOMERATES OF POLYSTYRENE OBTAINED BY FREEZE-DRYING OF ITS DILUTE SOLUTION

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Chinese Journal of Polymer Science 2002年第4期20卷 381-383页

作者： Song Wang Qing-hua Wang Rong-shi Cheng Research Center of Materials Beijing Institute of Technology Beijing 100081, china department of chemistry Nanjing University Nanjing 210093, china Nanjing Univ Dept Chem Nanjing 210093 Peoples R China Beijing Inst Technol Ctr Mat Res Beijing 100081 Peoples R China

The monomolecular particle agglomerates of polystyrenes were obtained by freeze-drying of its very dilute solutions of 1.3 x 10(-5)-2.0 x 10(-5) g/mL in benzene:cylcohexane (100:1) solvents, and they were annealed at room temperature for hundred days before use. According to C-13-NMR measurement the polystyrenes should be practically atactic. The number average molecular weights of the samples are 2.80 x 10(3), 2.00 x 10(4), and 1.55 x 10(6), respectively. The freeze-dried aPS with a molecular weight higher than 10(4) show two new IR absorption bands at 1098 and 1261 cm(-1), which are absent in the normal aPS and freeze-dried styrene oligomer. It was also found that the low molecular weight samples can only form powders, whereas the freeze-dried aPS with higher molecular weight form a mixture of powders and fibrils, of which the longer fibrils show a much stronger 1261 cm(-1) band than the shorter fibrils and the powder. It seems that the 1261 cm(-1) band corresponds to the stacking behavior of monomolecular particles.

关键词： monomolecular particles atactic polystyrene FTIR spectroscopy

CRYSTALLIZATION KINETICS OF HOMOGENEOUS AND HETEROGENEOUS LLDPE

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Chinese Journal of Polymer Science 2002年第4期20卷 339-345页

作者： Hong-xiang Teng Wen-hong Tang Yi Shi Xi-gao Jin State Key Laboratory of Polymer Physics and chemistry Center for Molecular Science, Institute of chemistry Chinese Academy of Sciences Beijing 100080 china department of chemistry Jilin University Changchun 130023, china Chinese Acad Sci Ctr Mol Sci Inst Chem State Key Lab Polymer Phys & Chem Beijing 100080 Peoples R China Jilin Univ Dept Chem Changchun 130023 Peoples R China

Based on thermal analysis, the isothermal and nonisothemal crystallization kinetics of Ziegler-Natta catalyzed linear low density polyethylene (Z-N LLDPE) and metallocene catalyzed LLDPE (m-LLDPE) were studied. Treating the results with the Avrami equation and the Ozawa equation, the crystallization constant Igk and the Avrami exponent n were obtained. Some other crystallization parameters were also discussed. According to the different characteristics of the chain structures of Z-N LLDPE and metallocene LLDPE, their crystallization behaviors were analyzed. It is indicated that the homogeneity and heterogeneity of the two polymers act in different way during the crystallization process of polymers, including the nucleation and the growth of crystals under various conditions.

关键词： crystallization kinetics homogeneity heterogeneity LLDPE

Syntheses and Crystal Structures of Sm（OAr）+2（THF）+3·THF and Sm（OAr）2（DME）2 （Ar =C6H2-tert-Bu3-2,4,6）

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Chinese Journal of Structural chemistry 2005年第10期 1152-1156+1103页

作者： YUAN Fu-Gena ZHU Xue-Huaa WENG Lin-Hongb a (department of chemistry, University of Science and Technology of Suzhou, Suzhou 215009, china) b (department of chemistry, Fudan University, Shanghai 200433, china)

Reaction of SmI2(THF)x with 2 equivalents of NaOAr (Ar = C6H2-tert-Bu3-2,4,6) in THF affords a divalent complex of Sm(OAr)2(THF)3?THF 1 in 90.8% yield. Treatment of 1 with 1,2-dimethoxyethane (DME) leads to the ligand-exchange reaction, and a DME-solvated complex of Sm(OAr)2(DME)2 2 was obtained. Complex 1 crystallizes in monoclinic, space group P21/c with a = 10.366(5), b = 33.024(15), c = 16.123(7) ?, β = 93.197(8)°, V = 5511(4) ?3, Z = 4, C52H90O6Sm, Mr = 961.59, Dc = 1.159 g/cm3, F(000) = 2048, μ(MoKα) = 1.107 mm-1, R = 0.0844 and wR = 0.1401 for 4694 observed reflections. Complex 2 crystallizes in monoclinic, space group C2/c with a = 27.222(5), b = 10.6140(19), c = 17.398(4) ?, β = 110.245(3)°, V = 4716.4(16) ?3, Z = 4, C44H78O6Sm, Mr = 853.41, Dc = 1.202 g/cm3, F(000) = 1808, μ(MoKα) = 1.285 mm-1, R = 0.0361 and wR = 0.0830 for 5210 observed reflections.

关键词： divalent samarium aryloxide azobenzene