Kobunshi - Vol. 59, No. 9 (September, 2010)

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Vol. 59, No. 9, September, (2010)

Surface Modification of Polypropylene Molded Sheets by Means of Surface-Initiated ATRP of Methacrylates
Tomoaki MATSUGI1, Junji SAITO1, Nobuo KAWAHARA1, Shingo MATSUO1, Hideyuki KANEKO1, Norio KASHIWA1, Motoyasu KOBAYASHI2, and
Atsushi TAKAHARA2,3
1Research Center, Mitsui Chemicals, Inc. 2JST-ERATO
3Institute for Materials Chemistry and Engineering, Kyushu University

Surface-initiated ATRP of methyl methacrylate (MMA) on the surface of structurally well-defined polypropylene-macroinitiator molded sheets was investigated. It was found that a high graft density PMMA brush was formed as a thin layer on the surface of the sheets. The thickness of the layer, the graft density, and the molecular weight of the PMMA were well controlled. Dynamic friction tests showed that the PMMA formed a stable layer because of the covalent bonding with the PP backbone vis-a-vis the PMMA-coating on the PP sheet. Furthermore, wettability and antibacterial properties of the PP sheet surface were revealed to improve drastically as a result of the surface-initiated ATRP of MTAC. Surface modifications as a result of this method can be applied to a variety of polyolefin moldings such as films, sheets, nonwoven fabrics, and injection-molded products. Polymer Journal 2009, 41, 547.

Enhanced Ionic Conduction in Organoboron Ion Gels Facilely Designed via Condensation of Cellulose with Boric Acids in Ionic Liquids
Noriyoshi MATSUMI1, Yusuke NAKAMURA1, Keigo AOI1, Takeshi WATANABE2, Tomonobu MIZUMO2, and Hiroyuki OHNO2
1Graduate School of Bioagricultural Sciences, Nagoya University
2Department of Biotechnology, Tokyo University of Agriculture and Technology
Novel organoboron ion-gels were facilely prepared by condensation between cellulose and boric acids in ionic liquids. The desired ion gels were effectively obtained under a wide range of material compositions. The ion gels exhibited ionic conductivity of 10-3-10-4 Scm-1 which was comparable to ionic liquids themselves. When pentafluorophenylboric acid was employed as boric acid, the obtained ion gel showed significantly higher ionic conductivity. Using the VFT (Vogel-Fulcher-Tammann) parameters, it was demonstrated that the carrier ion number of the matrices increased in the presence of highly dissociable lithium pentafluorophenylborate. The ion gels including low viscous formate type ionic liquid were also successfully prepared. Because of the lower activation energy of ion transport indicated from VFT parameters, a much improved ionic conductivity was observed. Polymer Journal 2009, 41, 437.

Synthesis of a Sun-Shaped Polymer by Macroinitiator Method via Lithiation of a Cyclic Poly(p-methylstyrene)
Yusuke HAMAGUCHI, Ryota UEMURA, Kaoru ADACHI, and Yasuhisa TSUKAHARA
Department of Chemistry and Materials Technology, Graduate School of Science and Technology, Kyoto Institute of Technology
A sun-shaped polymer, which is the unique polymer architecture composed of a cyclic backbone and numbers of linear branches, was synthesized by anionic polymerization using the "grafting-from" method. A cyclic polyanion macroinitiator was prepared by lithiation of methyl groups on cyclic poly(p-methylstyrene) with s-BuLi in the presence of TMEDA in cyclohexane. Subsequent addition of styrene monomer to the cyclic macroinitiater affords the increase of molecular weight of the polymer, which indicates the attainment of sun-shaped polymer architecture by anionic polymerization. Moreover, relatively narrow molecular weight distribution of the obtained sun-shaped polymer suggests the control of graft polymerization. Self-assembly of this polymer architecture might be interesting. Polymer Preprints, Japan 2010, 59, 133.

A Viscosity Self-Oscillation of Polymer Solution Induced by the Belousov-Zhabotinsky Reaction
Yusuke HARA
Nanosystem Research Institute, National Institute of Advanced Science and Technology (AIST)
The self-oscillating polymer chain exhibit cyclic soluble-insoluble changes under the constant temperature conditions of a closed system with coexistence of the Belousov-Zhabotinsky (BZ) substrates other than the metal catalyst. In this study, we succeeded in measuring a viscosity self-oscillation of the polymer solution induced by the BZ reaction under acid-free condition. The viscosity self-oscillation is attributed to the difference between viscosities for the polymer solution in the reduced and oxidized states. The viscosity self-oscillating behavior greatly depended on the polymer concentration and the temperature of the polymer solution. The period of the viscosity self-oscillation decreased with increasing temperature in accordance with the Arrhenius equation. We believe that the viscosity self-oscillation is originating in the autonomous change in the viscosity of the polymer solution and leads to a novel and wide variety of nonlinear phenomena and may inspire novel experimental and theoretical consideration. Journal of Chemical Physics, 2008, 128, 224904.

Molecular Recognition of Syndiotactic PMMA Helical Cavity
Takehiro KAWAUCHI
Department of Materials Science, Toyohashi University of Technology
An important characteristic arising from the helical structure is an inclusion ability into the inner helix. Syndiotactic poly(methyl methacrylate) (st-PMMA), a stereoregular commodity polymer, adopts a helical structure with a large cavity at the inner helix in toluene and encapsulates fullerenes such as C60 and C70 within the helical cavity to form a crystalline inclusion complex. We found that the st-PMMA folds into a helical conformation in response to the size of fullerenes through the inclusion complex formation, generating a selective extraction of C70 from a mixture of C60 and C70. Moreover, we succeeded in separation of higher fullerenes from a "fullerene mixture" by the preferential encapsulation. Polymer Preprints, Japan 2009, 58, 1618.

Liquid Crystalline Ordering Controls Hexagonal Cylinder Structure in Microphase-Separated Film
Motonori KOMURA
Chemical Resources Laboratory, Tokyo Institute of Technology
Homeotropic alignment of liquid crystal (LC) induces perpendicular orientation of microphase separated nanocylinders in an LC block copolymer (BC) film. We succeeded in imaging the nanocylinders with a high aspect ratio of 300 by originally developed AFM cross sectional measurement. In-situ AFM observation directly visualized sphere-cylinder order-order transition (OOT) in the formation process. Growth direction of the nanocylinder contradicts the conventional OOT phenomenon and is dominated by LC ordering, corresponding to GISAXS investigation. Moreover, long range ordering enhanced by blended low molecular (LM) LC affords a defect-free 102 ｵm2 microphase separated grain with a 103 aspect ratio of nanocylinders. Furthermore, we can control the nanocylinder orientation to not only perpendicular but also uniaxially parallel directions by the rubbing method special for LC orientation. Polymer Preprints, Japan 2009, 58, 3615.

Unusually Large Hysteresis of Temperature-Responsive a,a-Disubstituted Vinyl Polymers
Takeshi MORI1, Mohamed R. BERBER, and Yasushi MAEDA2
1Graduate School of Engineering, Kyushu University
2Department of Applied Chemistry and Biotechnology, Fukui University
A soluble-to-insoluble transition of temperature-responsive polymers generally shows very small hysteresis because of the rapid responding characters of hydration of polymer chains to a temperature change. We have recently succeeded in designing new polymers which show unusually large hysteresis. These polymers have two amphiphilic substituents at a-position. From the FT-IR observation, it was revealed that, after dehydration, the hydrogen bond (H-bond) between a pair of amide groups coupled with other pairs through H-bond network. This H-bonds coupling is similar to that of b-sheet proteins. These polymers are interesting not only as a new temperature-responsive material with a unique property but also as a model of an enhanced hysteresis of proteins in their folding process. Langmuir. DOI: 10.1021/la100020t. J. Phys. Chem. B. DOI: 10.1021/jp102681q.

One-step Preparation of Glycosyl Monomers for Chemo-enzymatic Polysaccharide Synthesis from Unprotected Sugars
Masato NOGUCHI, Tomonari TANAKA, Atsushi KOBAYASHI, and Shin-ichiro SHODA
Department of Biomolecular Engineering, Tohoku University
The chemo-enzymatic process is one of the most convenient methods for polysaccharide synthesis. Activated sugar derivatives are used as monomers for the glycosidase- catalyzed polymerization reaction. However, the synthesis of the activated sugar derivatives was laborious because a multi-step process including protection and deprotection of hydroxy groups is necessary. Here we report the development of a direct synthesis of the glycosyl monomers for glycosidase-catalyzed polymerization reaction in aqueous media. Sugar oxazoline derivatives are used as monomers for the synthesis of chitin, hyaluronic acid and glycosaminoglycans. The direct preparation of the oxazoline derivatives are achieved by using 2-chloro-1,3-dimethylimidazolinium chloride(DMC) as a condensing agent in aqueous media. 4-(4,6-dimethoxy-1,3,5-triazin-2-yl) glycosides, new activated sugar derivatives for the synthesis of b-glucan, are directly synthesized from free saccharides by using the water soluble condensing reagent, 4-(4,6-dimethoxy-1,3,5- triazine-2-yl)-4-methylmorphorinium chloride (DMT-MM). Polymer Preprints, Japan 2008, 57, 190. J. Org. Chem., 2009, 74, 2210.

Oscillating Soft Actuators of Hydrogel Particles
Takeshi KOBAYASHI, Toshihiro HIRAI, Ryo YOSHIDA, and Daisuke SUZUKI
International Young Researchers Empowerment Center, Shinshu University
Soft polymer actuators have attracted much attention as smart materials, and they could be used as artificial muscles, microlenses, and sensors. In general, hydrogel actuators respond to their surroundings such as pH and temperature. Herein, we will demonstrate oscillating soft actuators driven by a chemical cyclic reaction. In order to construct the actuators, hydrogel particles (microgels) were assembled, and then covalently crosslinked. Because of their fast responsiveness to the surroundings, the actuators can show large volume change in oscillation. In particular, we have found that the oscillating amplitude of the actuator induced by dispersing/flocculating oscillation became much bigger compared to simple swelling/ deswelling oscillation. The new type of actuator may find applications such as in micropumps. Polymer Preprints, Japan 2010, 59, 337.