研究者詳細 - 中西　和樹

論文 - 中西　和樹

分割表示 412 件中 181 - 200 件目／全件表示 >>

Structure and properties of polymethylsilsesquioxane aerogels synthesized with surfactant <i>n</i>-hexadecyltrimethylammonium chloride 査読有り

Hayase, G; Kanamori, K; Nakanishi, K

MICROPOROUS AND MESOPOROUS MATERIALS 158 巻頁： 247 - 252 2012年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Microporous and Mesoporous Materials

Structure and physical properties of monolithic polymethylsilsesquioxane (PMSQ, CH 3SiO 1.5) aerogels have been systematically examined with varied starting compositions using a sol-gel system containing surfactant n-hexadecyltrimethylammonium chloride (CTAC). The precursor methyltrimethoxysilane (MTMS) undergoes hydrolysis and polycondensation under an acid-base two-step reaction to obtain uniform gels as a one-pot reaction. To compare the samples, each factor of starting composition, such as amount of CTAC, concentration of aqueous acetic acid solution, volume of solvent and amount of urea, is independently varied. With appropriate concentrations of surfactant CTAC, the aerogels with high light transmittance (at 550 nm) are obtained, owing to the effective suppression of macroscopic phase separation. Acid-base catalysts, acetic acid and urea also impose significant effects on the properties of obtained aerogels including their molecular-level structures. The aerogel with 91% of light transmittance was obtained under an optimized condition. The lowest density of the PMSQ aerogel in this system reaches 0.045 g cm -3. © 2012 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.micromeso.2012.03.049

Synthesis of Monolithic Hierarchically Porous Iron-Based Xerogels from Iron(III) Salts via an Epoxide-Mediated Sol-Gel Process 査読有り

Kido, Y; Nakanishi, K; Miyasaka, A; Kanamori, K

CHEMISTRY OF MATERIALS 24 巻 ( 11 ) 頁： 2071 - 2077 2012年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemistry of Materials

Various iron-based polycrystalline monoliths, Fe 3O 4, iron, and Fe 3C, with hierarchically distributed pores have been synthesized from ionic precursors using a sol-gel process accompanied by phase separation. Propylene oxide acts as a proton scavenger to increase pH moderately and uniformly in a reaction solution, which leads to homogeneous gelation. On the other hand, poly(acrylamide) works as a phase separation inducer as well as a precipitation inhibitor. Appropriate choice of iron precursor, solvent, polymer, and epoxide allowed the formation of iron(III)-based xerogels with cocontinuous macroporous structures. The dried gels were amorphous, whereas heating in air above 300 °C led to the formation of α-Fe 2O 3. Calcination under an inert condition above 400 °C formed Fe 3O 4, iron, and Fe 3C without collapse of macrostructures. Examination has been carried out using SEM, TG-DTA, FT-IR, Hg intrusion, pH measurement, X-ray diffraction, and N 2 adsorption-desorption. © 2012 American Chemical Society.

DOI： 10.1021/cm300495j

Facile preparation of macroporous graphitized carbon monoliths from iron-containing resorcinol-formaldehyde gels 査読有り

Hasegawa, G; Kanamori, K; Nakanishi, K

MATERIALS LETTERS 76 巻頁： 1 - 4 2012年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Materials Letters

In this report, we demonstrate the facile preparation of macroporous monolithic materials based on graphitized carbon by utilizing catalytic graphitization at relatively low temperature (1000°C). The precursor polymer, macroporous resorcinol-formaldehyde (RF) xerogel, can be obtained without any surfactants or polymeric additives in water/ethanol mixed solvent via the sol-gel reaction accompanied by phase separation. The use of iron chloride as an acid catalyst for polymerization provides the RF monoliths incorporated with Fe, which catalyzes the graphitization. The effects of the starting composition on the morphologies of the resultant RF gels and the characteristics of the graphitized carbon monoliths have been discussed. © 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.matlet.2012.02.069

Pore properties of hierarchically porous carbon monoliths with high surface area obtained from bridged polysilsesquioxanes 査読有り

Hasegawa, G; Kanamori, K; Nakanishi, K

MICROPOROUS AND MESOPOROUS MATERIALS 155 巻頁： 265 - 273 2012年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Microporous and Mesoporous Materials

Hierarchically porous carbon monoliths with high specific surface area have been prepared via a nano-phase extraction technique from carbon/silica composites which had been prepared from arylene-bridged polysilsesquioxanes. The nano-sized silica phase developed in the composite has been removed to increase micropores, resulting in a similar effect to thermal activation of carbons. The resultant carbons are expected to possess homogeneously distributed micropores. Here we report the changes of the pore characteristics through the synthesis process by the nitrogen adsorption-desorption method and mercury porosimetry. In particular, the growth of silica phase in carbon/silica composites at different temperatures has been characterized by the micropore analysis using the Horváth-Kawazoe method. © 2011 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.micromeso.2012.02.001

Development of flexible porous materials from organotrialkoxysilanes 査読有り

Kazuyoshi Kanamori, Gen Hayase, Kazuki Nakanishi

Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy 59 巻 ( 6 ) 頁： 320 - 325 2012年6月

記述言語：日本語掲載種別：研究論文（学術雑誌）

Organosiloxane (RnSiO(4-n)/2) gels can be prepared from organoalkoxysilanes using the sol-gel process. In general,however, formation of uniform networks from these precursors is strongly inhibited due to cyclization reactions. In addition, phase separation of hydrophobic condensates from polar solvent leads to inhomogeneous gels in these systems. A careful control of the hydrolysis and polycondensation reactions is therefore required to obtain a monolithic gel with desired properties. We have been trying to control the sol-gel reactions as well as phase separation in these systems to obtain unique porous materials particularly from methyltrimethoxysilane(MTMS) and dimethyldimethoxysilane (DMDMS). Flexible aerogels and xerogels based on the methylsiloxane networks are discussed.

DOI： 10.2497/jjspm.59.320

Flower-like surface modification of titania materials by lithium hydroxide solution 査読有り

Hasegawa, G; Kanamori, K; Sugawara, Y; Ikuhara, Y; Nakanishi, K

JOURNAL OF COLLOID AND INTERFACE SCIENCE 374 巻 ( 1 ) 頁： 291 - 296 2012年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Colloid and Interface Science

Surface modification of titania materials to give flower-like structures has been achieved simply by the treatment in lithium hydroxide aqueous solution under mild conditions. The flower-like structured materials were characterized by X-ray diffraction, thermogravimetric analysis, and Raman scattering. The analyses indicate that the flower-like materials are composed of layered hydrous lithium titanate. It is suggested that the unique intercalation behavior of lithium ions into titania allows dissolution and re-precipitation of titania to form the flower-like structure. The obtained flower-like structure can be retained up to 700°C, while the crystal phase transforms into Li 4Ti 5O 12. © 2012 Elsevier Inc.

DOI： 10.1016/j.jcis.2012.02.002

New Monolithic Capillary Columns with Well-Defined Macropores Based on Poly(styrene-<i>co</i>-divinylbenzene) 査読有り

Hasegawa, G; Kanamori, K; Ishizuka, N; Nakanishi, K

ACS APPLIED MATERIALS & INTERFACES 4 巻 ( 5 ) 頁： 2343 - 2347 2012年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACS Applied Materials and Interfaces

Macroporous polymer monoliths based on poly(styrene-co-divinylbenzene) with varied styrene/divinylbenzene ratios have been prepared by organotellurium- mediated living radical polymerization. The well-defined cocontinuous macroporous structure can be obtained by polymerization-induced spinodal decomposition, and the pore structures are controlled by adjusting the starting composition. The separation efficiency of small molecules (alkylbenzenes) in the obtained monoliths has been evaluated in the capillary format by high-performance liquid chromatography (HPLC) under the isocratic reversed-phase mode. Baseline separations of these molecules with a low pressure drop (∼2 MPa) have been achieved because of the well-defined macropores and to the less-heterogeneous cross-linked networks. © 2012 American Chemical Society.

DOI： 10.1021/am300552q

3官能性/2官能性ケイ素アルコキシド共重合による柔軟多孔性ゲルの作製

早瀬元, 金森主祥, 中西和樹

日本セラミックス協会　年会・秋季シンポジウム講演予稿集 2012 巻 ( 0 ) 頁： 280-280 2012年

記述言語：英語掲載種別：研究論文（学術雑誌）

エアロゲルの力学的強度を改善するため、非反応性のメチル基により柔軟性や低い架橋密度を実現した有機-無機ハイブリッドエアロゲルがこれまでに研究されてきた。本研究においては3官能性ケイ素アルコキシドmethyltrimethoxysilane (MTMS) と2官能性アルコキシドdimethyldimethoxysilane (DMDMS) を前駆体、<I>n</I>-hexadecyltrimethylammonium chloride (CTAC) を相分離抑制のための界面活性剤として用い、酢酸と尿素を使った酸性/塩基性触媒による2段階ゾル－ゲル反応でエアロゲルを合成することに成功している。この出発組成を変化させることでエアロゲルの微細構造や結合を制御し、密度・力学特性の変化を調べた。

DOI： 10.14853/pcersj.2012S.0.280.0

612 高効率イオン交換反応の実現に向けたバルク型マクロ多孔性層状腹水酸化物の作製(セラミック/ナノ材料の創製,セラミック/ナノ材料の創成と評価,オーガナイスドセッション8)

徳留靖明, 樽谷直紀, 高橋雅英, 中西和樹

学術講演会講演論文集 61 巻頁： 159-160 2012年

Evolution of Mesopores in Monolithic Macroporous Ethylene-Bridged Polysilsesquioxane Gels Incorporated with Nonionic Surfactant 査読有り

Mushiake, A; Kanamori, K; Nakanishi, K

INTERNATIONAL JOURNAL OF POLYMER SCIENCE 2012 巻 2012年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：International Journal of Polymer Science

By combining the micellar templating in nanometer scale with the polymerization-induced phase separation in micrometer scale, ethylene-bridged polysilsesquioxane gels with hierarchical macropores and mesopores are prepared. The difference of mesopore structures depending on the method of the solvent removal has been observed by the X-ray diffraction and the nitrogen adsorption-desorption measurements. During the hydrothermal treatment under the basic condition, the reorganization of the polysilsesquioxane gel network occurred differently depending on the alkoxy group contained in the precursors. From 29Si CP/MAS NMR measurements, it was revealed that the crosslinking density of the hydrothermally treated gels was increased so that the highly ordered mesostructure of the wet gel could be preserved even after the evaporative drying of solvent. © 2012 Atsushi Mushiake et al.

DOI： 10.1155/2012/460835

2011 Donald R. Ulrich Awards 査読有り

K. Nakanishi

Journal of Sol-Gel Science and Technology 頁： 1 - 2 2012年

マクロ多孔性導電性酸化物Ti<SUB><I>n</I></SUB>O<SUB>2<I>n</I>－1</SUB> (<I>n</I> = 2, 3, 4, 6)モノリス体の選択的作製査読有り

北田敦, 長谷川丈二, 小林洋治, 金森主祥, 中西和樹, 陰山洋

日本セラミックス協会年会・秋季シンポジウム講演予稿集 2012 巻 ( 0 ) 頁： 526 - 526 2012年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：公益社団法人日本セラミックス協会

細孔特性の精密な制御が可能な相分離法によって，細孔サイズが一様で，連続したマクロ孔をもつシリカやアルミナ，チタニアなどのマクロ多孔性酸化物モノリス体が得られているが、従来の報告は全て絶縁体であった．我々は相分離法により得られたTiO<SUB>2</SUB>のマクロ多孔性モノリス体に対して，金属ジルコニウムを用いた還元反応を行い，一連の酸素欠損型チタン酸化物Ti<SUB><I>n</I></SUB>O<SUB>2<I>n</I>－1</SUB> (<I>n</I> = 2, 3, 4, 6)のマクロ多孔性モノリス体をそれぞれ単相で作製した．得られた一連の還元体はTiO<SUB>2</SUB>前駆体の孔特性をほぼ完全に維持している．また従来の約半分のバルク密度(1.8 g cm<SUP>－3</SUP>)，約3倍の空孔率(60%)，そして同等の室温バルク抵抗率(2 × 10<SUP>－2</SUP> Ω cm)を有しており，様々な電極材料としての応用が考えられる．

DOI： 10.14853/pcersj.2012S.0.526.0

Role of block copolymer surfactant on the pore formation in methylsilsesquioxane aerogel systems 査読有り

Kurahashi, M; Kanamori, K; Takeda, K; Kaji, H; Nakanishi, K

RSC ADVANCES 2 巻 ( 18 ) 頁： 7166 - 7173 2012年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：RSC Advances

Transparent and low-density methylsilsesquioxane (MSQ, CH 3SiO 1.5) aerogels can be obtained solely from methyltrimethoxysilane (MTMS) by a one-pot two-step process under the co-presence of surfactant. In the present study, we have systematically investigated the effects of the molecular structure of triblock copolymer-type nonionic surfactants PEO-b-PPO-b-PEO (PEO and PPO denote poly(ethylene oxide) and poly(propylene oxide) units, respectively) on the properties of the resultant MSQ aerogels. Macroscopic phase separation of hydrophobic MSQ networks from polar solvent occurs when no surfactant is employed, which results in macroporous opaque aerogels. In contrast, a co-presence of appropriate surfactant effectively suppresses the phase separation and yields transparent aerogels after supercritical drying. By employing various surfactants having different molecular weight and PO/EO ratio, the mechanism of suppression of phase separation or pore formation is discussed in detail. In situ 1H NMR suggests that the PO units of surfactant interact with the hydrophobic MSQ network enriched with methyl groups and make the MSQ network hydrophilic by extending EO chains toward the aqueous solvent in the late phase of gelation, until which hydrogen bonding dominates between the Si-OH groups of polymerizing MSQ and the ether oxygens of the EO unit. Through the comprehensive understanding of the role of surfactant, the strategy for rational design of MSQ aerogels materials has become developable. © 2012 The Royal Society of Chemistry.

DOI： 10.1039/c2ra20799k

Facile Preparation of Monolithic LiFePO<sub>4</sub>/Carbon Composites with Well-Defined Macropores for a Lithium-Ion Battery 査読有り

Hasegawa, G; Ishihara, Y; Kanamori, K; Miyazaki, K; Yamada, Y; Nakanishi, K; Abe, T

CHEMISTRY OF MATERIALS 23 巻 ( 23 ) 頁： 5208 - 5216 2011年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemistry of Materials

A novel and facile method for the preparation of monolithic LiFePO 4/carbon composites with well-defined macropores has been developed. The precursor macroporous gels consisting of inorganic networks as well as organic polymers were fabricated by the epoxide-mediated sol-gel method accompanied by phase separation. The inorganic-organic hybrid gels were calcined under an inert atmosphere, resulting in LiFePO4/carbon monoliths. The influence of the starting compositions on the gel morphologies has been investigated, and the constituents of the gel network were discussed. The reaction mechanism of the crystallization of LiFePO4 from green bodies during calcination has also been investigated by thermal analysis, X-ray diffraction, and Raman scattering. In addition, the electrochemical properties of the resultant LiFePO4/carbon composites were examined by the charge-discharge test. © 2011 American Chemical Society.

DOI： 10.1021/cm2021438

Macroporous carbon monoliths with large surface area for electric double-layer capacitor

Hasegawa G., Aoki M., Kanamori K., Nakanishi K., Hanada T., Tadanaga K.

Materials Research Society Symposium Proceedings 1304 巻頁： 38 - 43 2011年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Materials Research Society Symposium Proceedings

Macro/meso/microporous carbon monoliths doped with sulfur have been prepared from sulfonated polydivinylbenzene networks followed by the activation with CO 2 resulted in the activated carbon monoliths with high surface area of 2400 m 2 g -1. The monolithic electrode of the activated carbon shows remarkably high specific capacitance (175 F g -1 at 5 mV s -1 and 206 F g -1 at 0.5 A g -1). © 2011 Materials Research Society.

DOI： 10.1557/opl.2011.604

Synthesis of new flexible aerogels from di- and trifunctional organosilanes

Hayase G., Kanamori K., Nakanishi K., Hanada T.

Materials Research Society Symposium Proceedings 1306 巻頁： 68 - 73 2011年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Materials Research Society Symposium Proceedings

Recent years, although silica aerogels are expected to be the promising material for energy savings, the lack of mechanical strength prevents from commercial applications such as to low-density thermal insulators. To improve mechanical properties, methyltrimethoxysilane (MTMS) and dimethyldimethoxysilane (DMDMS) are used in this study as the co-precursor of aerogels because the network becomes flexible due to the relatively low cross-linking density and to the unreacted methyl groups. Because of the strong hydrophobicity of MTMS/DMDMS-derived condensates, phase separation occurs in aqueous sol and must be suppressed to obtain uniform and monolithic gel. We employed surfactant n-hexadecyltrimethylammonium chloride (CTAC) in starting compositions to control phase separation during a 2-step acid/base sol-gel reaction. By changing the starting composition, various microstructures of pores are obtained. In the uniaxial compression test, the aerogel showed high flexibility and spring-back to the original shape after removing the stress. © 2011 Materials Research Society.

DOI： 10.1557/opl.2011.216

Organosiloxane transparent aerogels and hierarchically porous monoliths

Kodera Y., Hayase G., Kanamori K., Nakanishi K., Hanada T.

Materials Research Society Symposium Proceedings 1306 巻頁： 54 - 59 2011年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Materials Research Society Symposium Proceedings

A transition of porous structures in monolithic poly(methylsilsesquioxane) (PMSQ, CH 3SiO 1.5) gels from uniform mesopores to hierarchical pore structures consisting of macro- and mesopores, has been investigated using a sol-gel system containing surfactant Pluronic F127. A broad variation of porous morphology is controlled by changing the concentration of F127. Sufficient concentrations of F127 inhibit the occurrence of macroscopic phase separation of hydrophobic PMSQ condensates and lead to well-defined mesoporous transparent aerogels with high specific pore volume. Mesopores are developed through microscopic phase separation of PMSQ colloid-surfactant complexes in the solvent. Macroscopic phase separation regulates well-defined macropores in the micrometer range on decreasing concentrations of F127, in which microscopic phase separation concurrently takes place in the PMSQ-rich gelling phase after the onset of macroscopic phase separation. Monolithic PMSQ gels with hierarchical macro- and mesopore structures are consequently obtained. © 2011 Materials Research Society.

DOI： 10.1557/opl.2011.96

Hierarchically Porous Materials by Phase Separation: Monoliths

Kazuki Nakanishi

Hierarchically Structured Porous Materials: From Nanoscience to Catalysis, Separation, Optics, Energy, and Life Science 頁： 241 - 267 2011年11月

Hierarchically Structured Porous Materials: Application to Separation Sciences

Kazuki Nakanishi

Hierarchically Structured Porous Materials: From Nanoscience to Catalysis, Separation, Optics, Energy, and Life Science 頁： 517 - 529 2011年11月

New hierarchically porous titania monoliths for chromatographic separation media 査読有り

Hasegawa, G; Morisato, K; Kanamori, K; Nakanishi, K

JOURNAL OF SEPARATION SCIENCE 34 巻 ( 21 ) 頁： 3004 - 3010 2011年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Separation Science

Separation media based on hierarchically porous titania (TiO2) monoliths for highperformance liquid chromatography (HPLC) have been successfully fabricated by the sol-gel process of titanium alkoxide in a mild condition utilizing a chelating agent and mineral salt. The as-gelled TiO 2 monoliths were subjected to a simple solvent exchange process from ethanol (EtOH) to H2O followed by drying and calcination. The resultant monolithic TiO2 columns consist of anatase crystallites with the typical specific surface area of more than 200m2/g. The resultant monolithic TiO2 column calcined at 200 and 400°C exhibited a good separation performance for organophosphates as well as for polar benzene derivatives in the normal-phase mode. © 2011 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim.

DOI： 10.1002/jssc.201100538

その他リンク： http://orcid.org/0000-0002-8069-4780

　前のページ - 次のページ　

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21