研究者詳細 - 中西　和樹

論文 - 中西　和樹

分割表示 412 件中 221 - 240 件目／全件表示 >>

Macro- and microporous carbon monoliths with high surface areas pyrolyzed from poly(divinylbenzene) networks 査読有り

Hasegawa, J; Kanamori, K; Nakanishi, K; Hanada, T

COMPTES RENDUS CHIMIE 13 巻 ( 1-2 ) 頁： 207 - 211 2010年1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：Comptes Rendus Chimie

Carbon monoliths with well-defined macropores and high surface areas were prepared by carbonization of macroporous poly(divinylbenzene) (PDVB) monoliths. The carbonization reactions of PDVB networks are studied by thermal analysis and FT-IR measurements. According to the measurement results, the PDVB networks are mostly pyrolyzed at 430 °C and their structures dynamically change to graphite-like structure between 600 and 700 °C. The macropore structure retained while the mesopores disappeared after carbonization. In addition, the surface area of the obtained carbons dramatically increased over 900 °C. The typical carbon monolith carbonized at 1000 °C for 2 h had a surface area of 1500 m2 g-1 and uniform macropores with a diameter of 1 μm. © 2009 Académie des sciences.

DOI： 10.1016/j.crci.2009.04.003

Facile preparation of transparent monolithic titania gels utilizing a chelating ligand and mineral salts 査読有り

Hasegawa, G; Kanamori, K; Nakanishi, K; Hanada, T

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY 53 巻 ( 1 ) 頁： 59 - 66 2010年1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 Sol-Gel Science and Technology

Highly homogeneous transparent titania gels have been successfully prepared from titanium alkoxide by a sol-gel method utilizing chelating agent, ethyl acetylacetate (EtAcAc), in the presence of strong acid anions. Only catalytic amount of a strong acid anion suppress the rapid hydrolysis of titanium alkoxide by blocking the nucleophilic attack of HO- and H2O, and the resultant moderate sol-gel reactions thus afford homogeneous gelation, leading to transparent monolithic titania gels. Gelation time can be widely controlled by changing amounts of water, chelating agent and salt. The ability of salts to suppress the too abrupt sol-gel reactions is strongly dependent on the electronegativity of anions and valence of cations. With employing NH 4NO3 as a suppressing electrolyte, the obtained titania gels can be converted to pure TiO2 by simple washing and heat-treatment, and transformations to anatase and rutile structures were found to start at 400 and 600 °C, respectively. © 2009 Springer Science+Business Media, LLC.

DOI： 10.1007/s10971-009-2056-5

Hierarchically porous carbon monoliths with high surface area from bridged polysilsesquioxanes without thermal activation process 査読有り

Hasegawa, G; Kanamori, K; Nakanishi, K; Hanada, T

CHEMICAL COMMUNICATIONS 46 巻 ( 42 ) 頁： 8037 - 8039 2010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：Chemical Communications

Hierarchically porous carbon monoliths with high specific surface areas have been fabricated by removing nano-sized silica phase from carbon/silica composites pyrolyzed from bridged polysilsesquioxane. This activation method improves the homogeneity between inner and outer parts of the monoliths compared to the conventional thermal activation methods. © 2010 The Royal Society of Chemistry.

DOI： 10.1039/c0cc02974b

Effects of Starting Compositions on the Properties of Methylsilsesquioxane Aerogels 査読有り

Gen Hayase, Kazuyoshi Kanamori, Kazuki Nakanishi, Teiichi Hanada

MRS Online Proceedings Library Archive 1247 巻頁： 1247-C08-17 2010年

Sol-gel synthesis, porous structure, and mechanical property of polymethylsilsesquioxane aerogels 査読有り

Kanamori, K; Nakanishi, K; Hanada, T

JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 117 巻 ( 1372 ) 頁： 1333 - 1338 2009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：Journal of the Ceramic Society of Japan

Organic-inorganic hybrid aerogels with polymethylsilsesquioxane (PMSQ, CH3SiO1.5) composition have been synthesized by a modified two-step sol-gel process. The precursor alkoxysilane is hydrolyzed in a weakly acidic condition, and subsequently allowed to undergo polycondensation in a weakly basic condition which is brought up by the hydrolysis of urea. Two kinds of surfactant (nonionic and cationic) have been utilized to suppress macroscopic phase separation. The resultant porous morphology could be modified by the kind of surfactant used. Small angle X-ray scattering (SAXS) and nitrogen adsorption have been employed to assess the porous morphology and it is found that the obtained PMSQ aerogels consist of aggregated particles and each particle contains micropores. Compressive mechanical properties have also been discussed based on the obtained information on porous morphology. Copyright © 2009 The Ceramic Society of Japan.

DOI： 10.2109/jcersj2.117.1333

ワイドポアモノリスシリカカラムによるネイティブタンパク質の分離性能評価査読有り

森坂裕信, 桐野彩, 水口博義, 中西和樹, 植田充美

Chromatography 30 巻 ( Supplement 2 ) 頁： 42 - 43 2009年10月

Semi-micro-monolithic columns using macroporous silica rods with improved performance 査読有り

Morisato, K; Miyazaki, S; Ohira, M; Furuno, M; Nyudo, M; Terashima, H; Nakanishi, K

JOURNAL OF CHROMATOGRAPHY A 1216 巻 ( 44 ) 頁： 7384 - 7387 2009年10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 Chromatography A

Monolithic silica columns in semi-micro-format have been synthesized using poly(acrylic acid) as a phase-separation inducer via a sol-gel route. The absence of a thick skin layer accompanied by deformation of the micrometer-sized gelling skeletons on the outermost part of the macroporous silica rod contributed to improve the efficiency of monolithic silica columns as thick as 2.4 mm in diameter. The kinetic plot analysis revealed that monolithic silica columns with macropore diameter of 1 μm and skeleton thickness of 1 μm with decreased macroporosity behave similarly to columns packed with 3 μm particles with slightly lower back pressure. © 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.chroma.2009.05.028

Sol-gel synthesis of macro-mesoporous titania monoliths and their applications to chromatographic separation media for organophosphate compounds 査読有り

Konishi, J; Fujita, K; Nakanishi, K; Hirao, K; Morisato, K; Miyazaki, S; Ohira, M

JOURNAL OF CHROMATOGRAPHY A 1216 巻 ( 44 ) 頁： 7375 - 7383 2009年10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 Chromatography A

We have developed a method of independently tailoring the macro- and mesoporous structures in titania (TiO2) monoliths in order to achieve liquid chromatographic separations of phosphorous-containing compounds. Anatase TiO2 monolithic gels with well-defined bicontinuous macropores and microstructured skeletons are obtained via the sol-gel process in strongly acidic conditions using poly(ethylene oxide) as a phase separator and N-methylformamide as a proton scavenger. Aging treatment of the wet gels in the mother liquor at temperatures of 100-200 °C and subsequent heat treatment at 400 °C allow the formation and control of mesoporous structures with uniform pore size distributions in the gel skeletons, without disturbing the preformed macroporous morphology. The monolithic TiO2 rod columns with bimodal macro-mesoporous structures possess the phospho-sensitivity and exhibit excellent chromatographic separations of phosphorus-containing compounds. © 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.chroma.2009.06.016

Structural characterization of hierarchically porous alumina aerogel and xerogel monoliths 査読有り

Tokudome, Y; Nakanishi, K; Kanamori, K; Fujita, K; Akamatsu, H; Hanada, T

JOURNAL OF COLLOID AND INTERFACE SCIENCE 338 巻 ( 2 ) 頁： 506 - 513 2009年10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

Detailed nanostructures have been investigated for hierarchically porous alumina aerogels and xerogels prepared from ionic precursors via sol-gel reaction. Starting from AlCl3·6H2O and poly(ethylene oxide) (PEO) dissolved in a H2O/EtOH mixed solvent, monolithic wet gels were synthesized using propylene oxide (PO) as a gelation initiator. Hierarchically porous alumina xerogels and aerogels were obtained after evaporative drying and supercritical drying, respectively. Macroporous structures are formed as a result of phase separation, while interstices between the secondary particles in the micrometer-sized gel skeletons work as mesoporous structures. Alumina xerogels exhibit considerable shrinkage during the evaporative drying process, resulting in relatively small mesopores (from 5.4 to 6.2 nm) regardless of the starting composition. For shrinkage-free alumina aerogels, on the other hand, the median mesopore size changes from 13.9 to 33.1 nm depending on the starting composition; the increases in PEO content and H2O/EtOH volume ratio both contribute to producing smaller mesopores. Small-angle X-ray scattering (SAXS) analysis reveals that variation of median mesopore size can be ascribed to the change in agglomeration state of primary particles. As PEO content and H2O/EtOH ratio increase, secondary particles become small, which results in relatively small mesopores. The results indicate that the agglomeration state of alumina primary particles is influenced by the presence of weakly interacting phase separation inducers such as PEO. © 2009 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jcis.2009.06.042

Performance of wide-pore monolithic silica column in protein separation 査読有り

Morisaka, H; Kobayashi, K; Kirino, A; Furuno, M; Minakuchi, H; Nakanishi, K; Ueda, M

JOURNAL OF SEPARATION SCIENCE 32 巻 ( 15-16 ) 頁： 2747 - 2751 2009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：Journal of Separation Science

A monolithic wide-pore silica column was newly prepared for protein separation. The wide distribution of the pore sizes of monolithic columns was evaluated by mercury porosimetry. This column, as well as the conventional monolithic column, shows high permeability in the chromatographic separation of low-molecular-sized substances. In higher-molecular-sized protein separation, the wide-pore monolithic silica column shows better performance than that of the conventional monolithic column. Under optimized conditions, five different proteins - ribonuclease A, albumin, aldolase, catalase, and ferritin - were baseline-separated within 3 min, which is faster than that using the particle-packed columns. In addition, the monolithic wide-pore silica column could also be prepared in fused silica capillary (600 mm long, 0.2 mm i.d.) for highly efficient protein separation. The peak capacity of the wide-pore monolithic silica capillary column is estimated to be approximately 300 in the case of protein separation, which is a characteristic performance. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.

DOI： 10.1002/jssc.200800653

Rigid Crosslinked Polyacrylamide Monoliths with Well-Defined Macropores Synthesized by Living Polymerization 査読有り

Hasegawa, J; Kanamori, K; Nakanishi, K; Hanada, T; Yamago, S

MACROMOLECULAR RAPID COMMUNICATIONS 30 巻 ( 12 ) 頁： 986 - 990 2009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：Macromolecular Rapid Communications

We have developed a new way to obtain monolithic macroporous PBIS rigid networks consisting of continuous skeletons and macropores which are three-dimensionally interconnected by TERP accompanied by phase separation. The obtained PBIS networks have well-defined macropores with narrow pore size distributions. The pore size and the total pore volume are easily controlled by varying the amount of the solvent DMF and the phase separator PEO. The resultant networks leave relatively large BET surface areas by using supercritical drying. The obtained monoliths can be used in aqueous phase applications such as bioseparations and catalyst supports by copolymerizing or grafting with functional monomers such as N-isopropylacrylamide. & 2009 WILEY-VCH Verlag GmbH & Co. KGaA.

DOI： 10.1002/marc.200900066

Effect of La addition on thermal microstructural evolution of macroporous alumina monolith prepared from ionic precursors 査読有り

Tokudome, Y; Nakanishi, K; Hanada, T

JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 117 巻 ( 1363 ) 頁： 351 - 355 2009年3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 the Ceramic Society of Japan

Porous alumina monoliths with high thermal stability have been prepared using sol-gel processing from ionic precursors. Samples were synthesized from AlCl3·6H2O and LaCl3·7H 2O dissolved in a H2O/etanol solution containing poly(ethylene oxide) (PEO) via propylene oxide (PO) involved sol-gel reaction accompanied by phase separation. The heat-treated gels consist of controllable size of macropores and La-doped alumina skeletons. Doped lanthanum ions are homogeneously embedded in the gel matrix, which retards the phase transition from γ -alumina to α -alumina during the sintering. The 3 mol% La-doped aluminate exhibits the BET surface area of 55.3 m2/g, after the heat treatment at 1100°C for 24 h. Drying condition are also related to the thermal stability of obtained gels. Aluminate aerogels show higher thermal stability than corresponding xerogels due to relatively large mesopore size and high porosity. As a result, the 3 mol% lanthanum doped aluminate aerogel shows BET surface area as high as 82.5 m2/g even after heat treatment at 1100°C for 24 h. © 2009 The Ceramic Society of Japan. All rights reserved.

DOI： 10.2109/jcersj2.117.351

Pore Formation in Poly(divinylbenzene) Networks Derived from Organotellurium-Mediated Living Radical Polymerization 査読有り

Hasegawa, J; Kanamori, K; Nakanishi, K; Hanada, T; Yamago, S

MACROMOLECULES 42 巻 ( 4 ) 頁： 1270 - 1277 2009年2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：Macromolecules

Macroporous cross-linked polymeric dried gels have been obtained by inducing phase separation in a homogeneous poly(divinylbenzene) (PDVB) network formed by organotellurium-mediated living radical polymerization (TERP). The living polymerization reaction of DVB with the coexistence of a nonreactive polymeric agent, poly(dimethylsiloxane) (PDMS), in solvent 1,3,5- trimethylbenzene (TMB) resulted in polymerization- induced phase separation (spinodal decomposition), and the transient structure of spinodal decomposition has been frozen by gelation. Well-defined macroporous monolithic dried gels with bicontinuous structure in the micrometer scale are obtained after removing PDMS and TMB by simple washing and drying. Inside the skeletons that comprise the macroporous structure, "skeletal pores" with various sizes in nanometer scale have also been found by gas sorption measurements. The skeletal pores are deduced to be formed by secondary phase separation in the skeletons due to the thermodynamic instability that arises in the separated phases during the polymerization. The properties of the macropores and the skeletal pores have been controlled by changing starting composition, molecular weight of PDMS, and reaction temperature. © 2009 American Chemical Society.

DOI： 10.1021/ma802343a

Spinodal decomposition in siloxane sol-gel systems in macroporous media 査読有り

Kanamori, K; Nakanishi, K; Hanada, T

SOFT MATTER 5 巻 ( 16 ) 頁： 3106 - 3113 2009年

Elastic Aerogels and Xerogels Synthesized From Methyltrimethoxysilane (MTMS) 査読有り

Kazuyoshi Kanamori, Kazuki Nakanishi, Teiichi Hanada

POLYMER-BASED SMART MATERIALS - PROCESSES, PROPERTIES AND APPLICATION 1134 巻頁： 173 - + 2009年

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 SOC

Transparent organic-inorganic hybrid aerogels and aerogel-like xerogels have been prepared from methyltrimethoxysilane (MTMS) respectively by supercritical drying (SCD) and ambient pressure drying (APD). The new aerogels and xerogels significantly deform without collapsing on uniaxial compression and almost fully relax when unloaded. This elastic behavior., termed as "spring-back", allows APD without noticeable shrinkage and cracking. The flexible network composed of lower cross-linking density (up to three bonds per every silicon atom) compared to silica gels (up to four bonds) and repulsion between hydrophobic methyl groups bonded to every silicon atom largely contributes to the pronounced deformability and relaxing, respectively. Lower surface silanol group density also plays a crucial role for the "spring-back" behavior.

Preparation of Macroporous Poly(divinylbenzene) Gels Via Living Radical Polymerization 査読有り

Joji Hasegawa, Kazuyoshi Kanamori, Kazuki Nakanishi, Teiichi Hanada, Shigeru Yamago

POLYMER-BASED SMART MATERIALS - PROCESSES, PROPERTIES AND APPLICATION 1134 巻頁： 139 - + 2009年

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 SOC

Macroporous cross-linked polymeric dried gels have been obtained by inducing phase separation in a homogeneous poly(divinylbenzene) (PDVB) network formed by organotellurium-mediated living radical polymerization (TERP). The living polymerization reaction of DVB with the coexistence of a non-reactive polymeric agent, poly(dimethylsiloxane) (PDMS), in solvent 1,3,5-trimethylbenzene (TMB) resulted in polymerization-induced phase separation (spinodal decomposition), and the transient structure of spinodal decomposition has been frozen by gelation. Well-defined macroporous monolithic dried gels with bicontinuous structure in the micrometer scale are obtained after removing PDMS and TMB by simple washing and drying. The properties of the macropores have been controlled by changing starting composition.

Fabrication of macroporous silicon carbide ceramics by intramolecular carbothermal reduction of phenyl-bridged polysilsesquioxane 査読有り

Hasegawa, G; Kanamori, K; Nakanishi, K; Hanada, T

JOURNAL OF MATERIALS CHEMISTRY 19 巻 ( 41 ) 頁： 7716 - 7720 2009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：Journal of Materials Chemistry

Macroporous SiC ceramics were obtained from porous phenyl-bridged polysilsesquioxane prepared by a sol-gel method accompanied by spinodal decomposition subsequently subjected to intramolecular carbothermal reduction. By this method, we can obtain macroporous SiC ceramics with improved atomic-level homogeneity and controlled pore size more easily than by intermolecular carbothermal reduction using a mixture of SiO2 and carbon powder. Therefore, the resultant SiC ceramics have sufficiently high purity without washing with hydrofluoric acid to remove residual SiO 2. © The Royal Society of Chemistry 2009.

DOI： 10.1039/b913992c

Examination of mesopore structure of hierarchically macro/mesoporous silica by thermoporometry

Fukui E., Shinohara K., Nakanishi K., Kanamori K., Hanada T.

Materials Research Society Symposium Proceedings 1056 巻頁： 28 - 33 2008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：Materials Research Society Symposium Proceedings

Thermoporometry was employed to monitor the mesopore evolution in wet, drying and heat-treatment stages of monolithic macro/mesoporous silica with SBA-15 like structure. Direct comparison of mesopores in wet state was only possible with the samples extracted with sulfuric acid. In good agreement with the preceding study, the sulfuric acid not only removed the surfactant but also modified the silica gel network into that with reduced amount of micropores and increased stability against the drying stress. Thermoporometry revealed that the structural evolution takes place completely in the wet condition, which accompanies a decrease in the thickness of non-freezable water. © 2008 Materials Research Society.

Phase separation in silica sol-gel system containing anionic surfactant

Matsui T., Nakanishi K., Kanamori K., Hanada T.

Materials Research Society Symposium Proceedings 1056 巻頁： 418 - 423 2008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：Materials Research Society Symposium Proceedings

By inducing phase separation parallel to the sol-gel transition of alkoxy-derived silica systems, silica monoliths with well-defined co-continuous macropores were obtained from the systems containing anionic surfactants.We adopted three kinds of anionic surfactants which differ from each other in the length of alkyl chain (CH3(CH2)i7SO3Na, CH 3(CH2)i5SO3Na, CH3(CH 2)i3SO3Na).Mesopores were also found in the silica skeletons presumably by the supramolecular templating.Characterization of the dried or heat-treated samples was carried out by a scanning electron microscope (SEM) and nitrogen adsorption measurements.Experimental results showed that due to the moderate interaction between silica oligomers and surfactants, most of the surfactants are distributed to the solvent phase which determines the macropore volume.The median size and volume of the macropores could be controlled independently by the starting composition.In the absence of any additive to enhance templating by the surfactant, the samples exhibited only amorphous mesopores. © 2008 Materials Research Society.

Elastic organic-inorganic hybrid aerogels and xerogels 査読有り

Kanamori, K; Aizawa, M; Nakanishi, K; Hanada, T

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY 48 巻 ( 1-2 ) 頁： 172 - 181 2008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 Sol-Gel Science and Technology

Novel aerogels and xerogels with methylsilsesquioxane (MSQ, CH 3SiO1.5) networks have been prepared by a modified sol-gel process using surfactant and urea as a phase-separation inhibitor and as an accelerator for the condensation reaction, respectively. Optimized aerogels dried under a supercritical condition not only showed the similar properties as conventional pure silica aerogels such as high transparency and porosity etc, but also demonstrated outstanding mechanical strength against compression; the aerogel drastically shrank upon loading and then recovered when unloaded, which is called a "spring-back" behavior. On ambient pressure drying, the wet gel also exhibited the similar response against compression stress originated from the capillary pressure, and thus xerogels with the comparative structure and properties to those of corresponding aerogels have also been obtained. This unusual mechanical behavior is attributed to the trifunctional flexible networks of MSQ, low silanol concentration which prevents the irreversible shrinkage, and high concentration of a hydrophobic methyl group directly attached to every silicon atom which helps re-expansion after the temporal shrinkage. © 2008 Springer Science+Business Media, LLC.

DOI： 10.1007/s10971-008-1756-6

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