The Experts below are selected from a list of 93 Experts worldwide ranked by ideXlab platform

Yoshio Inoue - One of the best experts on this subject based on the ideXlab platform.

  • fast crystallization of poly 3 hydroxybutyrate and poly 3 hydroxybutyrate co 3 hydroxyvalerate with talc and boron nitride as nucleating agents
    Polymer International, 2005
    Co-Authors: Weihua Kai, Yoshio Inoue
    Abstract:

    The crystallization behavior of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) induced by two kinds of nucleating agents, boron nitride (BN) and talc, was investigated by differential scanning calorimetry, polarized optical microscopy and X-ray diffraction. Both BN and talc have good nucleating ability in the crystallization of PHB and PHBV. From these results, combined with Molecular Weight Measurement by gel permeation chromatography, the mechanism of nucleation by BN and talc in the crystallization of PHB and PHBV has been proposed. BN acts as a nucleating agent itself and initiates nucleation in the crystallization of PHB and PHBV. Talc acts in a different way. It reacts as a chemical reagent with the molten chains of PHB/PHBV, while the reaction product acts as the true nucleating agent, which lowers the crystallization barriers of PHB and PHBV. 1H NMR spectroscopy provides evidence for the reaction between PHB and talc and supports the proposed nucleation mechanism. Copyright © 2005 Society of Chemical Industry

Norio Manabe - One of the best experts on this subject based on the ideXlab platform.

  • Development of a novel potentiometric titration method for determination of polypropylene degradation
    Polymer Testing, 2005
    Co-Authors: Norio Manabe, Kenichi Kawamura, Masanao Ishikawa, Shoutarou Suzuki, Boping Liu, Minoru Terano, Hisayuki Nakatani
    Abstract:

    In this study, a novel potentiometric titration of hydroperoxide in degraded polypropylene (PP) is proposed. This titration is quite sensitive compared with the conventional ones such as UV and manual titrations, and its detection limit was about 2 meq/kg. The sensitivity was equal to that of Molecular Weight Measurement by GPC for the degraded PP and, in addition, the volatilization behavior of the hydroperoxide could be detected. This titration was found to be very effective for the determination of PP degradation.

  • Sample pretreatment for aggregate-free PVC Molecular Weight Measurement by size-exclusion chromatography
    Journal of Applied Polymer Science, 1998
    Co-Authors: Norio Manabe, K. Kawamura, T. Toyoda, H. Minami, M. Ishikawa, Sadao Mori
    Abstract:

    The procedure of aggregate-free poly(vinyl chloride) (PVC) solutions for size-exclusion chromatography (SEC) at room temperature using tetrahydrofuran (THF) as the mobile phase is proposed. PVC was dissolved in 1,2,4-trichlorobenzene (TCB) at 130 or 140°C for 6 h, precipitated in methanol, filtrated, and dried. The pretreated PVC was again dissolved in THF and SEC Measurements were performed at room temperature. High Molecular Weight (MW) PVC required a higher pretreatment temperature of 140°C. The existence of aggregates sometimes could not be observed by a refractive index detector, but a light-scattering detector attached to the SEC columns could detect them clearly. The slope of the relationship between the MW and retention volume at the high MW region was steep compared with that at the other part of the peak and it was also a good indicator of the existence of aggregates. The pretreatment of PVC resulted in the decrease in MW averages, which was attributed to the disappearance of aggregates and not to the degradation of PVC. The pretreatment at 150°C resulted in the degradation of PVC. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1801–1809, 1998

Hisayuki Nakatani - One of the best experts on this subject based on the ideXlab platform.

  • Development of a novel potentiometric titration method for determination of polypropylene degradation
    Polymer Testing, 2005
    Co-Authors: Norio Manabe, Kenichi Kawamura, Masanao Ishikawa, Shoutarou Suzuki, Boping Liu, Minoru Terano, Hisayuki Nakatani
    Abstract:

    In this study, a novel potentiometric titration of hydroperoxide in degraded polypropylene (PP) is proposed. This titration is quite sensitive compared with the conventional ones such as UV and manual titrations, and its detection limit was about 2 meq/kg. The sensitivity was equal to that of Molecular Weight Measurement by GPC for the degraded PP and, in addition, the volatilization behavior of the hydroperoxide could be detected. This titration was found to be very effective for the determination of PP degradation.

Weihua Kai - One of the best experts on this subject based on the ideXlab platform.

  • fast crystallization of poly 3 hydroxybutyrate and poly 3 hydroxybutyrate co 3 hydroxyvalerate with talc and boron nitride as nucleating agents
    Polymer International, 2005
    Co-Authors: Weihua Kai, Yoshio Inoue
    Abstract:

    The crystallization behavior of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) induced by two kinds of nucleating agents, boron nitride (BN) and talc, was investigated by differential scanning calorimetry, polarized optical microscopy and X-ray diffraction. Both BN and talc have good nucleating ability in the crystallization of PHB and PHBV. From these results, combined with Molecular Weight Measurement by gel permeation chromatography, the mechanism of nucleation by BN and talc in the crystallization of PHB and PHBV has been proposed. BN acts as a nucleating agent itself and initiates nucleation in the crystallization of PHB and PHBV. Talc acts in a different way. It reacts as a chemical reagent with the molten chains of PHB/PHBV, while the reaction product acts as the true nucleating agent, which lowers the crystallization barriers of PHB and PHBV. 1H NMR spectroscopy provides evidence for the reaction between PHB and talc and supports the proposed nucleation mechanism. Copyright © 2005 Society of Chemical Industry

John S Philo - One of the best experts on this subject based on the ideXlab platform.

  • size exclusion chromatography with on line light scattering absorbance and refractive index detectors for studying proteins and their interactions
    Analytical Biochemistry, 1996
    Co-Authors: J Wen, T Arakawa, John S Philo
    Abstract:

    Techniques of using size-exclusion chromatography (SEC) with on-line light-scattering, uv absorbance, and refractive index detectors to characterize the polypeptide Molecular Weights of simple proteins or glycoproteins or to determine the stoichiometry of protein complexes are described. Two unique advantages of this approach over conventional SEC are that the Molecular Weight Measurement is independent of elution position and can exclude the contributions from carbohydrates. When a protein or complex contains no carbohydrates, a two-detector method, i.e., light scattering combined with refractive index, can be used to calculate the Molecular Weight. When a protein contains carbohydrates, a three-detector method is used to calculate the Molecular Weight of polypeptide alone. Finally, a self-consistent three-detector method is used to determine the stoichiometry of a protein complex containing carbohydrates. Example applications for all these methodologies are described.