Co-reporter:Toshiaki Taniike, Patchanee Chammingkwan, Vu Q. Thang, Keisuke Goto, Tadahiro Fujitani, and Minoru Terano
The Journal of Physical Chemistry C November 2, 2017 Volume 121(Issue 43) pp:24085-24085
Publication Date(Web):October 12, 2017
DOI:10.1021/acs.jpcc.7b08242
The preparation of model Ziegler–Natta (ZN) surfaces under ultrahigh vacuum necessitates the activation of MgCl2 films deposited on a substrate, since these films unexceptionally expose the energetically most stable but catalytically inactive (001) face. Here, we present a method to activate MgCl2 films with the inactive (001) termination, which was based on the chemisorption of a Lewis base in an analogous way to industrial powder catalyst preparation. We found that a (001)-terminated MgCl2 film on Cu(110) was activated into a MgCl2·Lewis base adduct when exposed to a pyridine vapor at a nearly saturated vapor pressure. A dynamic response of the MgCl2 film to the chemisorption and desorption of a Lewis base was uncovered using low-energy electron diffraction and temperature-programmed desorption.
Co-reporter:Dai Xuan Trinh, Thuy Phuong Nhat Tran, Toshiaki Taniike
Separation and Purification Technology 2017 Volume 177(Volume 177) pp:
Publication Date(Web):28 April 2017
DOI:10.1016/j.seppur.2017.01.004
•A composite membrane was prepared by depositing UiO-66 nanoparticles on the regenerated cellulose membrane.•The composite membrane showed 100% methylene blue rejection at extremely high permeability.•The rejection originated from a pore sieving mechanism.•The membrane was stable in water, reuse and bending.A new type of MOF-polymer composite membranes was fabricated by depositing UiO-66 nanoparticles into a regenerated cellulose membrane. The UiO-66 nanoparticles filled the pore of the support membrane to offer selective pathways. The filtration performance of the new composite membranes was demonstrated for ultra/nano filtration of methylene blue (MB) and polyethylene glycol of different molecular sizes in aqueous solution. The perfect rejection of MB was attained at extremely high permeation flux compared with commercially available polymer membranes. The origin of the permeability and rejection was attributed to fluxes passing mainly through the intraparticle porosity of UiO-66 with the size cut-off between 1.22 and 2.28 nm. The unique membrane structure as well as the stability of UiO-66 in water enabled consistent filtration performance against bending and reuse.
Co-reporter:Koyuru Nakayama, Anh T.N. Dao, Kengo Takeuchi, Jun’ichi Shimokata, Toshiaki Taniike
Polymer Degradation and Stability 2017 Volume 144(Volume 144) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.polymdegradstab.2017.08.010
In this work, the oxidative degradation of recombinant spider silk in a solid state was studied based on chemiluminescence analysis. It was found that the chemiluminescence behavior of the recombinant spider silk closely resembled that of aliphatic polyamide: The emission developed without any induction time, and the maximum intensity was observed in the range of 480–520 nm. In combination with infrared spectroscopy, it was concluded that the oxidative degradation of the recombinant spider silk initiates mainly through the hydroperoxide formation at the Cα position of amino acid residues, and its unimolecular decomposition produces imide or α-keto amide groups together with the CL emission.
Co-reporter:Patchanee Chammingkwan, Fumitaka Yamaguchi, Minoru Terano, Toshiaki Taniike
Polymer Degradation and Stability 2017 Volume 143(Volume 143) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.polymdegradstab.2017.07.024
The influence of isotacticity and its distribution on the degradation behavior of polypropylene (PP) was examined on a series of PP fractions prepared with the aid of temperature rising elution fractionation technique. It was found that the length of the isotactic sequence predominantly decided the stability of PP fractions, where a faster propagation of oxidation occurred for PP chains with a longer isotactic sequence. Two PP fractions with different tacticity were mixed as the simplest model of polymer to examine the degradation behavior when the primary structure is distributed. It was found that even if two samples have the same average mesopentad, the details of the constituent differentiate their stability, which can be explained as a consequence of infectious degradation spreading.
Co-reporter:Bulbul Maira, Patchanee Chammingkwan, Minoru Terano, Toshiaki Taniike
Composites Science and Technology 2017 Volume 144(Volume 144) pp:
Publication Date(Web):26 May 2017
DOI:10.1016/j.compscitech.2017.03.026
Polypropylene (PP)/TiO2 and PP/Al2O3 nanocomposites were fabricated based on a new technology that involves the impregnation of metal alkoxide precursors in the porosity of PP reactor granule and subsequent conversion of the precursors into oxides during melt mixing. The so-called reactor granule technology enabled in-situ generation of highly dispersed oxide nanoparticles over a wide range of the loading extending up to 20 wt% without the use of dispersants. The confinement of metal alkoxide precursors in the porosity of the PP reactor granule and their facile chemical conversion into oxides were found to be crucial for the dispersion of the nanoparticles. The excellent dispersion of Al2O3 nanoparticles led to significant improvements in tensile properties, dielectric constants, and thermal conductivity as compared to conventional nanocomposites using a compatibilizer. It was concluded that the reactor granule technology is a simple and versatile way for the fabrication of polyolefin-based nanocomposites with superior functionalities.
Co-reporter:Anh T. N. Dao;K. Nakayama;J. Shimokata;T. Taniike
Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 6) pp:1049-1060
Publication Date(Web):2017/02/07
DOI:10.1039/C6PY01954D
Recent successes in the production of recombinant spider silk have boosted numerous attempts for its industrialization as a robust and extremely tough material. In spite of the acceleration of the materials science, the inherent weakness of the spider silk against harsh environments has not been sufficiently addressed. Here, the thermal degradation of recombinant spider silk powder was systematically studied under an oxidative atmosphere, based on multilateral characterization including thermogravimetric analysis (TGA), chemiluminescence (CL), nuclear magnetic resonance (NMR), X-ray diffraction (XRD), IR spectroscopy, and X-ray photoelectron spectroscopy (XPS). Spectroscopic changes throughout the degradation were analyzed using a spectral expression of correlation coefficients for resolving the structural and conformational modification of recombinant spider silk. The combination of the comprehensive characterization and statistical analysis clarified a crucial role of oxidative degradation. TGA exhibited a mass loss behavior of recombinant spider silk, typical for the auto-oxidation of polymers. Oxidation significantly promoted the decomposition of recombinant spider silk with chemiluminescence emission. We also identified the formation of carbonyl species as the main oxidation product, the preferential decomposition of amino acid residues in the amorphous phase, and aromatization and Tyr dimerization that could account for discoloration.
Co-reporter:Ryuki Baba;Ashutosh Thakur;Patchanee Chammingkwan;Minoru Terano
Dalton Transactions 2017 vol. 46(Issue 36) pp:12158-12166
Publication Date(Web):2017/09/19
DOI:10.1039/C7DT02492D
A series of silsesquioxane-supported Phillips-type molecular catalysts for ethylene polymerization were synthesized by introducing various functional groups in proximity to monoalkylated Cr(III). They were moderately active in ethylene polymerization, while the performance was sensitive to the type of functional group. In particular, the presence of a lone pair near the active center was found to enhance the activity and expand the molecular weight distribution, which is plausibly due to alkylaluminum temporally captured by the lone pair. A similar result was never obtained by adding free molecules bearing a lone pair, and the fixation of the lone pair near the active site was essential. It was revealed that the design strategy based on the support functionalization can be transferred to SiO2-supported chromium catalysts.
Co-reporter:Akanksha Matta, Ikki Katada, Junji Kawazoe, Patchanee Chammingkwan, Minoru Terano, Toshiaki Taniike
Polymer Degradation and Stability 2017 Volume 142(Volume 142) pp:
Publication Date(Web):1 August 2017
DOI:10.1016/j.polymdegradstab.2017.05.032
A novel approach for the stabilization of polypropylene (PP) has been proposed, which is based on the addition of a hyperbranched polymer (HBP) to reversibly trap stabilizer molecules in the dendritic interior and to prevent their volatilization. The lifetime of PP was at maximum 493% elongated by the addition of a small amount of HBP, which itself never suppressed the oxidative degradation, but effectively delayed the volatilization of stabilizers. The stabilization effect of HBP was further signified in the case of PP/SiO2 nanocomposites: HBP was grafted to SiO2 surfaces during melt mixing and was better dispersed through the nanoparticles in the matrix, providing 776% improvement in the lifetime. The versatility of the strategy was also confirmed for a variety of hindered phenols.
Co-reporter:Airong Qiagedeer, Bulbul Maira, Roman Strauss, Yue Zhao, Patchanee Chammingkwan, Goro Mizutani, Toshiaki Taniike
Polymer 2017 Volume 127(Volume 127) pp:
Publication Date(Web):3 October 2017
DOI:10.1016/j.polymer.2017.09.003
•New technology to prepare PP/noble metal nanocomposites.•Ag and Au nanoparticles are generated inside pores of PP reactor granule.•Pore encapsulation minimizes sintering and leaching of nanoparticles.•Excellent dispersion, non-linear optical and antibacterial properties.The present contribution reports a novel strategy to prepare polypropylene (PP)-based nanocomposites with highly dispersed noble metal nanoparticles (NPs), which includes the impregnation of a metal salt inside the porosity of PP reactor granule and subsequent in-situ generation of the NPs therein. Thus formed nanoparticles were confined and retained in the porosity, thus minimizing the sintering and leaching of the NPs during melt processing. The so-called reactor granule technology was applied to successfully prepare PP-based nanocomposites with Ag and Au NPs, and unique nonlinear optical properties and the antibacterial ability of the PP/Ag nanocomposites were demonstrated.Download high-res image (266KB)Download full-size image
Co-reporter:Bulbul Maira;Patchanee Chammingkwan;Minoru Terano
Macromolecular Materials and Engineering 2015 Volume 300( Issue 7) pp:679-683
Publication Date(Web):
DOI:10.1002/mame.201500012
A novel additive-free reactor granule technology is reported for the fabrication of polyolefin-based nanocomposites, which involves in situ generation of nanoparticles with unprecedented dispersion even at high filler loadings. Polypropylene reactor powder obtained by catalyzed propylene polymerization is first impregnated with magnesium ethoxide (Mg(OEt)2) solution. After the solvent drying and pre-hydrolysis, the powder is melt mixed to convert partially hydrolyzed Mg(OEt)2 into magnesium hydroxide (Mg(OH)2). Thus, prepared PP/Mg(OH)2 composites exhibit uniform dispersion of the in situ formed Mg(OH)2 nanoparticles even at a high filler loading (e.g., 20 wt%) without the use of dispersants, which is unexpected for the combination of hydrophilic filler and hydrophobic matrices. The obtained nanocomposites significantly improve the flame retardancy at a filler loading much lower than those for conventional composites.
Co-reporter:Naoki Aratani, Ikki Katada, Koyuru Nakayama, Minoru Terano, Toshiaki Taniike
Polymer Degradation and Stability 2015 Volume 121() pp:340-347
Publication Date(Web):November 2015
DOI:10.1016/j.polymdegradstab.2015.09.025
A high-throughput chemiluminescence imaging instrument is developed to realize facile and systematic data accumulation in degradation and stabilization of polymer. The instrument works based on imaging chemiluminescence of 100 oxidatively degrading polymer samples that are placed in a multi-cell with arrayed wells being flushed with atmospheric gas, and thereby enables simultaneous acquisition of 100 chemiluminescence curves. The present study reports validation and demonstrative application of the instrument for the oxidative degradation of stabilized polypropylene with a variety of hindered phenol anti-oxidants. Based on quantitatively accurate and large-volume data on oxidative induction time, not only the feasibility of the new instrument but also a number of useful aspects of stabilizers are demonstrated.
Co-reporter:Toshiki Funako;Patchanee Chammingkwan;Minoru Terano
Macromolecular Reaction Engineering 2015 Volume 9( Issue 4) pp:325-332
Publication Date(Web):
DOI:10.1002/mren.201400074
The present article proposes a simple way to dramatically alter the pore architecture of Mg(OEt)2-based Ziegler–Natta catalysts by the addition of a small amount of i-propanol during the synthesis of Mg(OEt)2. The incorporated i-propoxide distorts the crystalline structure of Mg(OEt)2, finally causing the phase transformation and significant densification of particles. Such modifications completely alternate the pore architecture of resultant catalysts, which contribute to the design of catalytic properties.
Co-reporter:Ashutosh Thakur;Supawadee Poonpong;Minoru Terano
Macromolecular Reaction Engineering 2014 Volume 8( Issue 11) pp:766-770
Publication Date(Web):
DOI:10.1002/mren.201400014
Abstract
The stopped-flow (SF) technique has been extensively used for active site analyses and kinetic investigations in heterogeneous Ziegler-Natta olefin polymerization catalysis, whereas a poor polymer yield due to a short polymerization period has been a major drawback of the conventional SF system, which later has been improved by the development of a large-scale SF (LSF) technique. In order to further improve the scalability of the LSF technique, the present paper reports a new polymerization quenching method, which has been established by applying a three-vessel-type analogue of the LSF system. The new quenching method endows identical kinetic profiles, but the scalability is successfully improved.
Co-reporter:Patchanee Chammingkwan;Vu Quoc Thang;Minoru Terano
Topics in Catalysis 2014 Volume 57( Issue 10-13) pp:911-917
Publication Date(Web):2014 June
DOI:10.1007/s11244-014-0251-2
Recently we successfully established the first structure–performance relationships between the catalyst surface area and propylene polymerization activity using novel MgO/MgCl2/TiCl4 core–shell catalysts with non-porous and non-fragmentable features. In the present paper, we have addressed the physical and chemical natures of these novel model catalysts in comparison with typical Ziegler–Natta catalysts, by means of comprehensive characterization and analyses. It was clarified that the MgO/MgCl2/TiCl4 core–shell catalysts offer an ideal and powerful tool to address relationships between the support architectures and polymerization performance, which had been long un-clarified.
Co-reporter:Kengo Takeuchi, Minoru Terano, Toshiaki Taniike
Polymer 2014 Volume 55(Issue 8) pp:1940-1947
Publication Date(Web):10 April 2014
DOI:10.1016/j.polymer.2014.03.003
Polypropylene (PP)/silica nanocomposites were prepared by the sol–gel reaction of silicon alkoxide that was impregnated in the confined amorphous nanospace of PP with the aid of supercritical carbon dioxide. This novel technique enabled us to prepare nanocomposites having a variety of silica morphology without altering the higher-order structures of PP, being ideal to study relationships between the silica morphology and mechanical properties of the nanocomposites. The synthesized silica particles were highly dispersed in PP with dimensions comparable to the amorphous thickness (<10 nm), while their mass fractal dimension acquired by small-angle X-ray scattering was dependent on the sol–gel conditions. We found that the Young's modulus as well as the storage modulus in melt viscoelastic measurements was negatively correlated with the mass fractal dimension of silica nanoparticles: A lower mass fractal dimension resulted in not only higher reinforcement but also percolation network formation at a lower silica loading.
Co-reporter:Kiwamu Tonosaki, Toshiaki Taniike, Minoru Terano
Journal of Molecular Catalysis A: Chemical 2011 340(1–2) pp: 33-38
Publication Date(Web):
DOI:10.1016/j.molcata.2011.03.005
Co-reporter:Toshiaki Taniike, Minoru Terano
Journal of Catalysis (September 2012) Volume 293() pp:39-50
Publication Date(Web):1 September 2012
DOI:10.1016/j.jcat.2012.06.001
Systematic periodic density functional calculations were conducted to clarify the mechanism for donors to exert steric and electronics influences on propylene polymerization using heterogeneous Ziegler–Natta catalysts. It was concluded that TiCl4 preferentially adsorbs as mononuclear species on the MgCl2 (1 1 0) surface, and the coadsorption of donors with it is energetically viable. The coadsorption of donors on the (1 1 0) surface reinforces the electron density of the Ti mononuclear species and sterically transfers the underlying C2 symmetry to convert the originally aspecific mononuclear species into isospecific one. The nearest coadsorption of ethylbenzoate (EB) not only sterically induces the isospecificity of the Ti mononuclear species but also electrostatically improves the regiospecificity in propylene insertion. In addition, EB prevents sterically demanding chain transfer to propylene, increasing the molecular weight of the produced polypropylene. Thus theoretically derived “coadsorption model” is highly consistent with a variety of experimentally known facts and believed to be useful for the ab initio prediction of new donor structures.Graphical abstractSystematic density functional calculations have been conducted to elucidate molecular roles of donors in heterogeneous Ziegler–Natta propylene polymerization. Coadsorption of donors with Ti mononuclear species on the MgCl2 (1 1 0) surface, which is energetically advantageous, can reproduce a variety of experimental facts such as the improvements in the stereo- and regiospecificities, the increase in polymer molecular weight.Download high-res image (145KB)Download full-size imageHighlights► DFT calculations on roles of donors in Ziegler–Natta propylene polymerization. ► Coadsorption of donors with TiCl4 mononuclear species on the MgCl2 (1 1 0) surface. ► Coadsorbed donors amplify surface C2 symmetry to induce the stereospecificity. ► Coadsorbed donors enrich the Ti electron density to enhance the regiospecificity. ► A theoretically and experimentally consistent “coadsorption model” is proposed.
Co-reporter:Taira Tobita, Patchanee Chammingkwan, Minoru Terano, Toshiaki Taniike
Polymer Degradation and Stability (March 2017) Volume 137() pp:131-137
Publication Date(Web):March 2017
DOI:10.1016/j.polymdegradstab.2017.01.012
Co-reporter:Linh Hoang Le, Dai Xuan Trinh, Nguyen Ba Trung, Thuy Phuong Nhat Tran, Toshiaki Taniike
Carbon (April 2017) Volume 114() pp:
Publication Date(Web):April 2017
DOI:10.1016/j.carbon.2016.12.029
The increasing number of studies on graphene membranes has indicated a great potential of graphene in separation applications. For the first time, this study demonstrates liquid permeation performance of a new graphene membrane that assembled functionalized graphene sheets. Functionalized graphene was synthesized from graphene dispersion based on a Bingel reaction with diethyl bromomalonate, and employed to prepare an assembled membrane using a vacuum filtration method. Thus prepared membrane was subjected to permeation tests using four solvents (hexane, acetone, methanol and water). The chemical functionalization led to two interesting consequences: i) Even a relatively minor extent of functionalization dramatically altered the chemical selectivity of the membrane, and ii) the permeability of the membrane was greatly enhanced, which plausibly arose from the less ordered stacking of the functionalized graphene sheets as compared to the pristine ones.
Co-reporter:Kengo Takeuchi, Bulbul Maira, Minoru Terano, Toshiaki Taniike
Composites Science and Technology (1 March 2017) Volume 140() pp:
Publication Date(Web):1 March 2017
DOI:10.1016/j.compscitech.2016.12.025
A template method is a powerful technique to tailor the morphology of formed nanomaterials. The present paper for the first time demonstrated the sol-gel reaction templated by the higher-order structure of semi-crystalline polymer. Silicon alkoxide was impregnated into the amorphous space of polypropylene (PP) with the aid of supercritical CO2, and subsequently converted into uniformly dispersed silica nanoparticles. The size and anisotropy of silica nanoparticles were controlled through the amorphous thickness of PP that was preliminarily defined through the crystallization process. We also studied the impact of the silica morphology on physical properties of resultant PP/silica nanocomposites. The silica morphology was systematically varied, keeping relatively uniform dispersion. We revealed that the storage modulus of the nanocomposites was well correlated with the size and anisotropy of the nanoparticles.
