| POLYMERS Vol.67 No.7 |
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COVER STORY
Separation of Polymers and Separation with Polymers |
| COVER STORY: Highlight Reviews |
| Removal of Organic Pollutants by Cyclodextrin Polymers | Toshiyuki KIDA |
| <Abstract> Cyclodextrins (CDs), which are produced from starch, are a class of cyclic oligosaccharides consisting of several α-(1,4)-linked D-glucose units. They have a cavity of sub-nanometer size, into which a variety of guest molecules can be incorporated. The ability of CDs to form inclusion complexes with guest molecules has been studied academically, and applications in various industrial fields including food, cosmetics, and pharmaceuticals have been developed. Many attempts have also been made to remove organic pollutants from the water using the inclusion ability of CDs. Here I will introduce recent studies on the removal of organic pollutants using CD polymers, while reviewing previous studies. Keywords: Cyclodextrin / Organic Pollutants / Removal / Recovery / Recycle / Molecular Recognition / Inclusion Complex |
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| Polymer Separations | Yo NAKAMURA |
| <Abstract> Polymers have a variety of structues, such as chain-end structure, monomer structure, copolymer structure, branching structure, and so on. To analyze such structures, separation techniques are important. Recently, various approaches have been proposed to improve the efficiency of separating polymers. This article reviews some new methods to analyze complex polymers by chromatographic techniques. Keywords: Size-Exclusion Chromatograpy / Liquid Chromatography at Critical Condition / Temperature Gradient Interaction Chromatograpy / 2D Chromatography / Field-Flow Fractionation / Multi-Angle Light Scattering Instrument |
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| COVER STORY: Topics and Products |
| Fractionation of Industrial Polymers | Eiichi TAKATORI |
| <Abstract> Polymer industries often have three analytical issues in the material development process. Those are molecular weight, its distribution, and branching. These properties’ analysis must be done after the fractionation of polymer materials. The GPC is a well-used equipment for molecular weight fractionation. GPC can be useful even in the case of cellulose. For the analysis of branching one of the most powerful mehods is a GPC equipped with MALS and viscometry. In many cases researchers believe that these procedures bring them a perfect analytical result. But in some cases we should consider several limitations of these procedures. Examples of these limitations are the relationship between Mw and molecular size in GPC, the so called absolute Mw through MALS, and the one-point-procedure intrinsic viscosity. Keywords: GPC / SEC / Molecular Weight / Fractionation / MALS / Intrinsic Viscosity |
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| Composition and Structure Analyses of Polymers in Polymer Materials by HPLC | Nobuyuki SATO |
| <Abstract> Liquid Chromatography at Critical Condition (LCCC) of adsorption for solid phase of a macromolecule is useful to separate two polymers even if each polymer cannot be separated in Size Excusion Chromatography (SEC) after solvent extraction from polymer materials. Eluent gradient HPLC can separate each polymer with its critical condition in a polymer blend by changing the composition of mobile phase from 100% poor solvent to 100% good solvent. It also works for sequece analysis (or randomness evaluation) in the copolymer consisting of two kinds of monomer. 2D-HPLC which carrys out a SEC for each fraction of eluent gradient HPLC can give the molecular weight distribution of copolymer as well as its composition distribution that is not available in other analytical methods such as NMR. Keywords: EC / LAC / LCCC / Epoxy / Copolymer / 2D-HPLC / Polymer Material / TGIC |
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| Development of Chiral Stationary Phases Using Helical Polymers | Katsuhiro MAEDA |
| <Abstract> The direct separation of enantiomers by high-performance liquid chromatography (HPLC) with the use of chiral stationary phases (CSPs) is a powerful method for both analytical and preparative purposes. A large number of CSPs have been developed for HPLC. In particular, optically active helical polymers are known to show excellent chiral recognition ability as CSPs. We recently found that optically inactive 2,2’-biphenol-derived polyacetylenes show reversible switching and memory of macromolecular helicity through non-covalent interactions with a chiral alcohol in the solid state as well as in solution. Using this unique feature, we succeeded in developing an unprecedented switchable CSP, in which the elution order of enantiomers can be switched at will. We also developed another type of switchable CSP using poly(phenylacetylene) bearing an optically active α-methoxyphenylacetic acid residue as the pendant, in which chiral recognition ability could be reversibly switched based on control of the macromolecular helicity by achiral metal cations. Keywords: Helical Polymers / Chiral Stationary Phase / HPLC / Chiral Recognition Ability / Elution Order |
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| Chiral Separation and Visualization Systems with Monoclonal Antibodies | Hiroyasu YAMAGUCHI, Akira HARADA |
| <Abstract> This article shows how optical isomers can be separated with high enantiopurity using monoclonal antibodies (mAbs). Both enantiomers can be successfully obtained by a simple one-step (column-free) procedure where mAbs are prepared for each enantiomer. The large difference in the molecular weights between the analyte and mAbs realizes the separation of the free analyte (chiral compound) by ultrafiltration. Chiral recognition by mAbs for a binaphthyl derivative (BN) is visualized using a thermoresponsive polymer, poly-N-isopropylacrylamide (pNIPAM) with BN. The hydration behavior of BN-modified pNIPAM is controlled by mAbs. We can clearly distinguish the atroposelective binding of mAbs for S- and R-isomers of BN by the naked eye. Keywords: Monoclonal Antibody / Chiral Separation / Ultrafiltration / Enantiomer / Molecular Recognition / Binaphthyl Derivatives / Thermoresponsive Polymer / Visualization |
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| Gas Separation by Polymer Membranes | Hiroaki YOSHIMIZU |
| <Abstract> There is no strong interaction between polymers and gases. Therefore, it can be said that the general princple of gas-separation by polymer membranes is diffusion controlling not affinity tuning. Some unique polymer crystals were useful and had high-potential for gas-separation, because the interchain distances between polymer chains were well-adjusting to the size of gas molecules. In addition, these crystals showed diffusion anisotrpy. The enhancement of gas diffusion and permeation properties was confirmed by mono-axially orienting the crystal with a magnetic field. This method is one of the proposals to obtain a good gas-separation polymer membrane. Keywords: Gas Separation / Gas Diffusion / Polymer Membrane / Polymer Crystal / Diffusion Anisotropy / Magnetic Orientation |
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| Polymer Science and I: A Personal Account |
| Inspirations from My Environment | Kazuya FURUSAWA |
| <Abstract> In my childhood, I have been interested in various things, such as insects, plastic models, and video games. Presently, I’m pursuing research in various fields, such as polymer science, tissue engineering, and food science. Therefore, I have many friends and colleagues with various backgrounds. The environment is really important for finding my research inspirations. |
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| Front-Line Polymer Science |
| Fractionation and Characterization of Macromolecular Complexes and Supermolecules | Kazuo SAKURAI |
| <Abstract> Characterizing self-assembled molecules in solutions plays an important role in not only analyzing polymeric materials but also regulatory science of nanomedicines. More accurate molecular analysis can be done by the use of recent advances in separation techniques such as Field-Flow Fractionation (FFF) combined with multiangle light scattering. This report briefly reviews recent studies on polymer micelles and supermolecules. Keywords: Molecular Fractionation / Gel Permeation Chromatography (GPC) / Field-Flow Fractionation (FFF) / Light Scattering / Molecular Conformation |
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