• 제목/요약/키워드: Functional Polymer

검색결과 782건 처리시간 0.027초

Molecularly Imprinted Polymers Having Amidine and Imidazole Functional Groups As an Enzyme-Mimetic Catalyst for Ester Hydrolysis

  • Chen, Wen;Han, Dong-Keun;Ahn, Kwang-Duk
    • Macromolecular Research
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    • 제10권2호
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    • pp.122-126
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    • 2002
  • A molecularly imprinted polymer (MIP) having both amidine and imidazole functional groups in the active site has been prepared using p-nitrophenyl phosphate as a transition state analogue (TSA). The imprinted polymer MIP with amidine and imidazole found to have the highest hydrolysis activity compared with other MIPs with either amidine or imidazole groups only. It is postulated a cooperative effect between amidine and imidazole in the hydrolysis of p-nitrophenyl methyl carbonate (NPMC) as a substrate when both groups were arranged in proximity by molecular imprinting. The rate enhancement of the hydrolysis by MIP was 60 folds over the uncatalyzed solution reaction and two folds compared with the control non-imprinted polymer CPI having both functional groups. The enzyme-mimetic catalytic hydrolysis of p-nitrophenyl acetate by MIP was evaluated in buffer at pH 7.0 with $K_{m}$ of 1.06 mM and $k_{cat}$ of 0.137 $h^{-1}$ . . .

Transition Metal-Mediated Living Radical Polymerization toward Precision Functional Polymers via Catalyst Design

  • Sawamoto, Mitsuo;Ouchi, Makoto
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.93-94
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    • 2006
  • This lecture will present an overview of recent advances in our transition metal-mediated living radical polymerization, particularly focused on catalyst design and precision synthesis of functional polymers. Selected topics will include: (A) Design of Transition Metal Complexes: Evolution of Catalysts (B) New Ruthenium and Iron Catalysts: Active and Versatile (C) Functional Methacrylates for Advanced Functional Polymers (D) Functional Star Polymers: Microgel Cores for Metal Catalysts.

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Feasibility study on the contact angle measurement by laser beam projection

  • Ahn, Seon-Hoon;Kim, Seong-Hun;Shin, Kyung-In;IM, Seung-Soon
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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    • pp.103-103
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    • 2003
  • A newly developed contact angle measurement instrument by laser beam projection allows for rapid and direct determination of contact angles. From the result of comparative experiment and questionnaire, the laser contact angle.

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Functional Polymers with Controlled Molecular Architecture: Design, Synthesis and Applications

  • Frechet Jean M.J.
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.1-2
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    • 2006
  • Polymer architecture plays a great role in determining the properties of functional polymers. This lecture will explore the design and the synthesis of polymers with controlled architecture and functionality. Especially featured will be star and dendritic architectures where the functional group placement and the molecular shape can be controlled. This will be followed by examples of applications illustrated with a few model systems of functional polymers designed for use in areas such as organic electronics, catalysis, surface patterning, separation and molecular recognition, and polymer therapeutics.

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Transient Protection of Intramolecular Hydrogen Bonding: A Simple but Elegant Approach for Functional Imaging

  • Kim, Jong-Man;Min, Sung-Jun;Park, Bum-Jun;Lee, Jae-Hyung;Ahn, Kwang-Duk
    • Macromolecular Research
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    • 제12권5호
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    • pp.493-500
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    • 2004
  • We have developed a novel method for patterning functional images in thin polymer films. The key materials we utilized for the imaging were dihydroxyanthraquinones protected with acid-labile tert-butoxycarbonyl (t-Boc) blocking groups. Among the tested compounds, 1,4-dihydroxyanthraquinone (quinizarin; 1) underwent the most drastic change in terms of its color and fluorescence upon protection. We prepared the t-Boc-protected quinizarin and polymers bearing the protected quinizarins as pendent groups. To investigate the possibility of a single-component imaging system, we synthesized a styrenic monomer 14 incorporating protected quinizarin and a maleimide derivative 15 bearing a photoacid generating group and subjected them to polymerization. Selective removal of the protecting groups of the quinizarin moieties in the exposed area using photolithographic techniques allowed regeneration of quinizarin and patterned fluorescence images in the polymer films.

Fully Rod-like Aromatic Polyimides: Structure, Properties, and Chemical Modifications

  • Moonhor Ree;Shin, Tae-Joo;Lee, Seung-Woo
    • Macromolecular Research
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    • 제9권1호
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    • pp.1-19
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    • 2001
  • Poly(p-phenylene pyromellitimide) and poly(4,4'-biphenylene pyromellitimide) are representatives of fully rod-like polyimides. Their structure and properties in thin films are reviewed. The polymers exhibit some excellent properties such as high molecular packing coefficient, high mechanical modulus, and low thermal expansion coefficient, and low interfacial stress, so that they are very attractive to both industry and academia. However, these polymers are very brittle and thus practically useless. Some chemical modifications to improve such drawback with a little sacrifice of the high modulus are described: i) incorporation of short side groups into the polymer backbone and ii) insertion of proper linkages into the polymer backbone.

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Photochromism of A Styrene-Derived Polymer Having Pendant Phenoxyanthraquinones

  • Ju, Sang-Yong;Ahn, Kwang-Duk;Han, Dong-Keun;Suh, Dong-Hack;Kim, Jong-Man
    • Journal of Photoscience
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    • 제7권4호
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    • pp.131-133
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    • 2000
  • A Styrene-derived polymer having pendent phenoxyanthraquinones for photochromism was prepared by AIBN-initiated radical polymerization. Syntgesus of the monomers was straightforward and the polymer was obtained in 65% yield. Photoinduced rearrangement from the “trans” quinone forms to the “ana” quinone forms readily occurred both in solution and in film when the polymer was irradiated with UV light.

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Fabrication of Pre-Exfoliated Clay Masterbatch via Exfoliation-Adsorption of Polystyrene Nanobeads

  • Khvan, Svetlana;Kim, Jun-Kyung;Lee, Sang-Soo
    • Macromolecular Research
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    • 제15권1호
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    • pp.51-58
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    • 2007
  • The approach studied in the present work produced an exfoliated state of clay layers via confinement of the charged nano-sized polystyrene (PS) beads within the gallery of swollen pristine clay. It was demonstrated that adsorption of the polymer nanobeads dramatically promotes expansion of the clay gallery. A comparative study of incorporation was conducted by employing organo-modified clay along with two different colloid polymer systems: electrostatically stabilized PS nanobeads and cationic monomer-grafted PS nanobeads. The mechanism of adsorption of the monomer-grafted polymer beads onto clay via cationic exchange between the alkyl ammonium group of the polymer nanobeads and the interlayer sodium cation of the layered silicate was verified by using several techniques. As distinct from the polymer nanobeads formed using conventional miniemulsion polymerization method, competitive adsorption of stabilizing surfactant molecules was be prevented by grafting the surface functional groups into the polymer chain, thereby supporting the observed effective adsorption of the polymer beads. The presence of surface functional groups that support the establishment of strong polymer-clay interactions was suggested to improve the compatibility of the clay with the polymer matrix and eventually play a crucial role in the performance of the final nanocomposites.