KOBUNSHI RONBUNSHU
Online ISSN : 1881-5685
Print ISSN : 0386-2186
ISSN-L : 0386-2186
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Volume 64, Issue 7
Displaying 1-10 of 10 articles from this issue
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Comprehensive Papers
  • Characterization of Cyclic Polystyrene with High Molecular Weight and Its Interdiffusion Behavior
    Daisuke KAWAGUCHI, Atsushi TAKANO, Yushu MATSUSHITA
    2007 Volume 64 Issue 7 Pages 397-405
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.397
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    In this paper, synthesis and characterization of cyclic polystyrenes (c-PS) including the structural feature of one of the derivatives and interdiffusion of c-PS are described. The cyclic structure of poly(styrenesulfonate), which was obtained by sulfonation of c-PS, was directly confirmed by atomic force microscopic observation. The purities of c-PS, evaluated by high performance liquid chromatography, were higher than 95%. The time-dependent interfacial thickness of a cyclic polystyrene (c-hPS)/its deuterated counterpart (c-dPS) bilayer film and that of a linear polystyrene (l-hPS)/its deuterated counterpart (l-dPS) bilayer film was investigated by dynamic secondary ion mass spectrometry (DSIMS) and neutron reflectivity (NR) measurement. The diffusion constant of c-PS is significantly larger than that of the corresponding linear one. This can be explained in terms of weaker topological constraint due to the lesser entanglement of c-PS.
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  • Dynamics of Polymer Blends and NMR Relaxation in Solids
    Atsushi ASANO
    2007 Volume 64 Issue 7 Pages 406-418
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.406
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    I investigated the relations among dynamics, structure, and miscibility for three kinds of miscible polymer blends: Poly(2-hydroxyethyl methacrylate)/poly(methacrylic acid) (PHEMA/PMAA), poly(methacrylic acid)/poly(vinyl acetate) (PMAA/PVAc), and polystyrene/ poly(vinyl methyl ether) (PS/PVME), using the high-resolution solid-state 13C cross-polarization magic-angle spinning (CPMAS) NMR technique. For the PHEMA/PMAA blends, the hydrogen bonding between side-chain OH of PHEMA and COOH of PMAA causes the molecular motion of PHEMA in the blends to be slow. This was suggested by the temperature dependence of 1H spin-lattice relaxation time in the rotating frame (T1ρH) and 13C CPMAS NMR spectra. Furthermore, the inter-polymer dehydration between the side-chain end groups of PHEMA and PMAA after heat treatment at 573 K for 10 min is found by 13C spin-lattice relaxation curve and 13C CPMAS NMR spectral analysis. For the PMAA/PVAc blends, each signal decomposed from a complicated signal at carboxyl and carbonyl region using the five Gaussian curves is assigned by the composition dependence of 13C spin-lattice relaxation time and the relative integrals. For the PS/PVME blends, observed multi-exponential T1ρH curves are successfully simulated with insufficient 1H spin-diffusion rate by assuming a three-spin system. The disagreements among the observed T1ρH curves are explained as due to the very fast molecular motion of PVME, which causes the 1H spin diffusion to be insufficient between PS and PVME.
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  • The Effects of Ultra-High Molecular Weight Components on Crystallization under Shear Flow
    Go MATSUBA, Koji NISHIDA, Toshiji KANAYA
    2007 Volume 64 Issue 7 Pages 419-428
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.419
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    This paper reports investigations on crystallization processes of polyethylene under shear flow. We used depolarized light scattering (DPLS), small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) techniques to reveal the effects of ultra-high molecular weight components in the polyethylene blends. The SANS/SAXS study on elongated blend showed that ultra-high molecular weight components exist in the micron-scaled structure aligned along the flow direction. The time-resolved DPLS and SAXS measurements showed that there existed a critical concentration of the ultra-high molecular weight polyethylene for the formation of the precursor of shish, suggesting that entanglements of ultra-high molecular weight chains play an important role. The role of chain relaxation in the shish-kebab formation was also discussed on the basis of the temperature dependence of the critical concentration.
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  • Hierarchical Thermal Molecular Motion in Thin Polymer Films
    Yohei TATEISHI, Keiichi AKABORI, Keiji TANAKA, Toshihiko NAGAMURA
    2007 Volume 64 Issue 7 Pages 429-436
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.429
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    Hierarchical thermal molecular motion was studied in thin films of polystyrene (PS). The segmental motion in the thin films was examined by dynamic mechanical analysis. Molecular motions with a relatively small scale in the thin films were discussed on the basis of the kinetics of photoinduced trans to cis isomerization for azobenzene probes tagged to PS. Apparent glass transition temperatures generally decreased with decreasing film thickness. Although relaxation temperatures of β and γ processes in the thin films would be comparable to those in the bulk, the photoisomerization reaction of azobenzene probes became faster with decreasing thickness. Finally, a model for hierarchical thermal molecular motions in thin films was proposed on the basis of the above-mentioned results.
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Original Papers
  • Transient Viscoelastic Properties of Lamellae-Forming Diblock Copolymers with Flow-Induced Alignment
    Yoshiaki TAKAHASHI, Kenta IMAICHI, Masahiro NODA, Atsushi TAKANO, Yush ...
    2007 Volume 64 Issue 7 Pages 437-440
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.437
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    The transient viscoelastic properties of lamellae-forming poly(styrene-block-2-vinylpyridine) and poly(styrene-d8-block-2-vinylpyridine) were measured to examine the alignment process of lamellae. Rescaled transient stress σ(t) after step increase of shear rate could not be scaled by strain or time, and the data showed poor reproducibility. σ(t) upon the onset of flow after a given rest time showed relatively large overshoot, while it instantaneously became steady upon the reverse of flow. These results suggest that the average degree of alignment is the same at the steady states, but the transient stresses are determined by the size and number of grains that undergo alignment.
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  • Force Spectroscopy on a Single Polymer Chain
    Ken NAKAJIMA, Naoto ONO, Kenji WATANABE, Toshio NISHI
    2007 Volume 64 Issue 7 Pages 441-451
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.441
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    A novel technique to extend the capability of atomic force microscopy (AFM) to force spectroscopy of a single polymer chain (nanofishing) is given together with its problems and perspective. Special emphasis is placed on the definition of the origin of extension length and the invalidity of existing theoretical models for quasi-static nanofishing. Dynamic nanofishing in cooperation with forced oscillation or with noise analysis is also given to discuss the viscoelastic nature of a single polymer chain. Fast nanofishing will reveal the intramolecular entanglement and its relaxation properties.
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  • Structure of Aggregates Formed by a Thermally Denatured Protein after Quench
    Aiko KONDO, Takahiro SATO
    2007 Volume 64 Issue 7 Pages 452-457
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.452
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    We have investigated the structure of aggregates formed by thermally denatured β-lactoglobulin in 0.1 M aqueous NaCl after quench at pH=7 and at a protein concentration ~10-3 g/cm3, using size exclusion chromatography equipped with a multi-angle light scattering detector (SEC-MALS), circular dichroism, and viscometry. While circular dichroism indicated an irreversible thermal denaturation of β-lactoglobulin in that solvent, viscometry demonstrated that β-lactoglobulin takes a random coil conformation upon heating and a compact one upon cooling. SEC-MALS results indicated that quenched β-lactoglobulin after denaturation exists as two kinds of aggregates in aqueous solution. From the molar mass obtained, we conclude that the major smaller aggregate comprises five β-lactoglobulin chains on average, and takes a compact conformation. The molar mass dependence of the radius of gyration for the larger aggregate was explained by the branched touched-bead model where the bead diameter was assumed to be the same as that of the smaller aggregate or the single protein molecule.
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  • Dynamic Viscoelastic Measurement of E. coli Giant DNA Solutions
    Taro KINOSHITA, Shihori SOHYA, Yutaka KURODA, Yuichi MASUBUCHI
    2007 Volume 64 Issue 7 Pages 458-463
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.458
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    Dynamic viscoelastic properties of E. coli giant DNA were measured. Double strand DNA of around 70 kbp extracted from cultivated E. coli was diluted by buffer solution to various concentrations. Successful measurements were achieved for certain concentrations and, for these concentrations, cross points between storage and loss moduli curves were observed. The obtained viscoelasticity values were in reasonable agreement with the primitive chain network simulation results. Concentration dependences of plateau modulus and relaxation time were consistent with the reptation theory.
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  • Size of Initial Structure Formed during Melt Crystallization of Crystalline Polymer in Relation to the Magnetic Alignment
    Masafumi YAMATO, Tsunehisa KIMURA
    2007 Volume 64 Issue 7 Pages 464-470
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.464
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    The structure that might exist in a melt or that is formed during the induction period of crystallization of polymers was studied in relation to the magnetic alignment of poly(ethylene terephthalate) (PET) and isotactic polystyrene (iPS). In situ infrared measurements in a magnetic field were carried out in a locally built apparatus that was equipped with an autorotation polarizer unit. For both PET and iPS, the degree of orientation was strongly dependent on which stage of the crystallization the magnetic field was applied. The magnetic alignment of PET and iPS was possible at the initial stage of crystallization, while it was impossible at a later stage because of high viscosity. The ordered structure in a melt state, possibly originating from the crystal before the melting, was aligned in the magnetic field in case of PET, while it was not so alignedin the case for iPS. These results indicate that the size of the order structure which exists in melt was less than 100 nm in the case of iPS and larger than 100 nm in the case of PET. In cases of both PET and iPS, we concluded that the structure formed during the induction period of crystallization was responsible for the magnetic alignment. The size of the structure responsible for the magnetic alignment was sub micrometer order.
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