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Yokkaichi, Japan

Takagi R.,Hiroshima University | Igata N.,Hiroshima University | Yamamoto K.,Hiroshima University | Yamamoto K.,Japan Polychem Corporation | Kojima S.,Hiroshima University
Journal of Molecular Catalysis A: Chemical | Year: 2010

Zirconocene dichloride (Cp2ZrCl2) supported on montmorillonite K-10, which has previously been shown to be an efficient catalytic system for olefin polymerization, was found to be comparable to the highly activated homogeneous combination of Cp2ZrCl2 and methylaluminoxane (MAO), and more reactive than the originally reported homogeneous catalytic system of Cp2ZrCl2/Me3Al in the methylalumination reaction of an aryl substituted terminal alkyne. Examination of solvent effects in the ethylalumination reaction using Cp2ZrCl2 supported on montmorillonite K-10, SiO2/LiOH, and SiO2/MgO, indicated that the anionic counterpart of the actual catalytically active zirconocenium cation is highly delocalized, thus suggesting that the actual active zirconocenium cation is only very weakly coordinating with the anionic moiety. This accounts for the high activity of systems using solids such as co-catalysts and as supporting materials in olefin polymerization in general. © 2010 Elsevier B.V. All rights reserved. Source


He Z.,CAS Institute of Chemistry | Liang Y.,CAS Institute of Chemistry | Liang Y.,Beijing Institute of Petrochemical Technology | Yang W.,CAS Beijing National Laboratory for Molecular | And 4 more authors.
Polymer (United Kingdom) | Year: 2015

A series of random hyperbranched linear polyethylene (RHBLPE), which represents a completely new type of polyethylene, was synthesized through a single step polymerizing process of ethylene by an α-diiminonickel complex pre-catalyst. The molecular weights, branching architectures, chemical compositional distributions as well as the crystallization behavior of these RHBLPEs were carefully investigated by GPC, NMR, A-TREF and DSC, respectively. The tensile properties and elastic recoveries at different temperatures were also explored. Moreover, their distinct elastomeric properties at different temperatures were observed and charactered. It has been determined that these properties are mainly affected by the crystallization behavior of RHBLPEs. The crystallization structures of these RHBLPEs were manipulated through the polymerization temperatures of the ethylene. Thus the elastic properties of RHBLPEs could be tailored to meet different application demands at wide temperature range (-20 to 65°C). © 2014 Elsevier Ltd. All rights reserved. Source


Ikehara T.,Kanagawa University | Kurihara H.,Japan Polychem Corporation | Kataoka T.,Kanagawa University
Journal of Polymer Science, Part B: Polymer Physics | Year: 2012

Spherulitic morphology and growth rate of block copolymers comprised of miscible crystalline constituents, namely poly(ethylene succinate) (PES) and poly(ethylene oxide) (PEO), were investigated. The results of the copolymers were compared with those of the blends with the same composition and molecular weight. Interpenetrating spherulites, where spherulites of one component grow in those of the other component, were observed in the copolymers as in the blends. Copolymerization, namely the connectivity of the PES and PEO blocks, reduced the spherulitic growth rate in the melt for both components. The growth inside the spherulites of the other component was discussed based on the lamellar and fibrillar (or lamella-stack) structures, which are influenced by the interblock connectivity. Suppression of molecular mobility in the interlamellar regions resulted in the reduced nucleation and growth rate of the component growing in the spherulites of the other constituent. PES of the copolymer showed dendrites around 60 °C or above. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 Crystallization and the formation of interpenetrating spherulites can create characteristic morphology in miscible copolymers. Spherulitic growth and morphology in block copolymers with two miscible crystalline components are reported, and the results are compared with those of the blends. The connectivity between the block chains in the copolymers influences the lamellar stack structures and crystallization dynamics. Copolymers form interpenetrating spherulites, where spherulites of one component grow in those of the other component, as in the blends. Copyright © 2012 Wiley Periodicals, Inc. Source


Yokomizo K.,Japan Polychem Corporation | Banno Y.,Japan Polypropylene Company | Kotaki M.,Kyoto Institute of Technology
Polymer (United Kingdom) | Year: 2012

Coarse-grained molecular dynamics simulation of a bead-spring polymer model was conducted for interdiffusion of two polymer flow fronts flowing parallel to one another as would be found in a weld-line. The effect of molecular orientation of the flow fronts on the interfacial structure was simulated. It was observed that the time evolution of the interfacial thickness was suppressed by shear flow for a chain whose length was longer than entanglement length. According to the analysis of autocorrelation function of end-to-end vector, it was revealed that anisotropic motion of chain was responsible for the growth of interfacial thickness and relaxation of the chain orientation was an important mechanism to explain the effect of shear flow on the growth of interfacial thickness. From the analysis of the segment motion at the interface with taking the density profile of end beads and center beads during the diffusion, it was found that interdiffusion of the end segment was always faster than that of center segments and significantly suppressed in oriented long chain. © 2012 Elsevier Ltd. Source


Kitade S.,Japan Polychem Corporation | Asuka K.,Japan Polypropylene Company | Akiba I.,University of Kitakyushu | Sanada Y.,University of Kitakyushu | And 2 more authors.
Polymer (United Kingdom) | Year: 2013

Shear-induced crystallization of a long chain hyper-branched polypropylene (LCB-PP, denoted PP-3) was carried out at a relatively high temperature of 170 °C, close to its melting temperature of 158 °C. Small-angle X-ray scattering (SAXS) showed that the intensity ratio of the normal to the perpendicular to the shear (V/H) was always larger than 1 for PP-3, indicating that shish-like structures were predominately formed and further growth to kebab was suppressed in PP-3. The crystallization behavior of PP-3 can be explained by the nature of PP-3 that there were a large amount of crystallization nuclei due to their branching points, and the point-like precursors formed from these nuclei were arrayed linearly along the shear direction and transformed into thread-like precursors or premature shishs; however, owing to the large amount of branching, further progress in crystallization was suppressed. © 2012 Elsevier Ltd. All rights reserved. Source

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