研究者詳細 - 中西　和樹

論文 - 中西　和樹

分割表示 412 件中 21 - 40 件目／全件表示 >>

Hierarchically Structured Porous Materials: Application to Separation Sciences 査読有り

Nakanishi, K

HIERARCHICALLY STRUCTURED POROUS MATERIALS: FROM NANOSCIENCE TO CATALYSIS, SEPARATION, OPTICS, ENERGY, AND LIFE SCIENCE 頁： 517 - 529 2012年

Controlled pore formation in organotrialkoxysilane-derived hybrids: from aerogels to hierarchically porous monoliths 査読有り

Kanamori, K; Nakanishi, K

CHEMICAL SOCIETY REVIEWS 40 巻 ( 2 ) 頁： 754 - 770 2011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 Society Reviews

Porous polysilsesquioxane gels derived from sol–gel systems based on trifunctional silanes are reviewed. Although it is well known that trifunctional silanes possess inherent difficulties in forming homogeneous gels, increasing attention is being paid on these precursors and resultant porous polysilsesquioxanes because of hydrophobicity, functionality, and versatile mechanical properties. Much effort has been made to overcome the difficulties for homogeneous gelation, and a number of excellent porous materials with various pore properties have been explored. In this critical review, we put special emphasis on the formation of a well-defined macroporous structure by making use of phase separation, which in turn is a serious problem in obtaining homogeneous gels though. Porous polysilsesquioxane monoliths with the hierarchical structure and transparent aerogels with high mechanical durability are particularly highlighted (169 references). © 2011 The Royal Society of Chemistry.

DOI： 10.1039/c0cs00068j

Facile Preparation of Hierarchically Porous TiO2 Monoliths 査読有り

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

JOURNAL OF THE AMERICAN CERAMIC SOCIETY 93 巻 ( 10 ) 頁： 3110 - 3115 2010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 the American Ceramic Society

Monolithic titania (TiO2) with multiscale porous structures have been successfully prepared via the sol-gel route accompanied by phase separation utilizing a chelating agent and mineral salt. The TiO2 gels obtained possess well-defined macropores derived from spinodal decomposition and mesopores as interstices of anatase TiO2 nanocrystallites.Most of the chelating agent were removed by hydrolysis and subsequent decarbonation through the gradual solvent exchange from ethanol to water. The TiO2 particles comprising TiO2 gel skeletons spontaneously converted from amorphous to anatase through the solvent exchange process in a mild condition at 60°C. The present method of the fabrication of porous TiO2 monoliths is advantageous for widespread applications because the reaction occurs under an almost neutral condition and does not require a hydrothermal process, which was indispensable to strengthen the monolith in the method previously reported © 2010 The American Ceramic Society.

DOI： 10.1111/j.1551-2916.2010.03831.x

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

Kanamori Kazuyoshi, Nakanishi Kazuki, Hanada Teiichi

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

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

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

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

Hierarchically porous oxides, hybrids and polymers via sol-gel accompanied by phase separation 査読有り

Nakanishi K.

Materials Research Society Symposium Proceedings 1007 巻頁： 51 - 62 2008年9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

In various crosslinking systems containing metal oxides, organo-siloxane polymers and pure hydrocarbons, monolithic materials with hierarchical well-defined macropores and controlled mesopores have been synthesized. Synthetic progress in alkoxy-derived macroporous silica lead to the preparation of long-range ordered mesoporous skeletons in well-defined macroporous framework. Alkylene-bridged silicon alkoxides can also be prepared into similarly hierarchical porous structures with broadened variations in framework morphology. Macro-mesoporous alkoxy-derived pure titania and zirconia have been prepared using hydrochloric acid - mediated processes. Compared with those prepared from colloidal dispersions, alkoxy-derived macroporous titania exhibited much higher mechanical strength. Titania monolith is a promising candidate as a separation medium to discriminate phosphorylated compounds in a liquid chromatography mode. Pure alumina macroporous monolith has been first synthesized from aluminum salt using propylene glycol as a proton scavenger to thrust the solution pH from acidic into neutral conditions. Alumina-based complex oxides such as garnets and spinels can also be prepared in pure phases. Polymerization and phase separation in organic crosslinker system was also controlled to obtain well-defined co-continuous macro-frameworks instead of those composed of aggregated particles. These examples demonstrate the versatility of using phase-separation in gelling systems to obtain well-defined macroporous structures. © 2007 Materials Research Society.

Web of Science

Scopus

researchmap

Phase separation in alkoxy-derived silica system containing polyacrylamide 査読有り

Kawamoto K., Nakanishi K., Hanada T.

Materials Research Society Symposium Proceedings 1007 巻頁： 63 - 68 2008年9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, gels having both macroporous and mesoporous structures can be obtained. Using poly(acrylamide) (PAAm) as a phase-separation inducer, macro/mesoporous silica gels were synthesized. After solvent exchange by water, the size distribution of mesopores of wet gels was evaluated by thermoporometry using a differential scanning calorimetry (DSC). Alternatively, gels were evaporation-dried after solvent exchange by ethanol or water/ethanol, followed by heat-treatment to completely remove volatile and organic components. Characterization of the dried or heat-treated samples was carried out using a scanning electron microscope (SEM) and by nitrogen adsorption measurements. Experimental results showed that the interaction between PAAm and silica is not so strong as the case of polymers having poly(oxyethylene) chains. The contribution of the secondary phase separation within the crosslinking silica-rich phase was suggested to be responsible for the mesopore formation in the PAAm-silica system. © 2007 Materials Research Society.

Web of Science

Scopus

researchmap

Phase separation in Al<inf>2</inf>O<inf>3</inf> sol-gel system incorporated with high molecular weight poly(ethylene oxide) 査読有り

Tokudome Y., Nakanishi K., Fujita K., Miura K., Hirao K.

Materials Research Society Symposium Proceedings 1007 巻頁： 69 - 74 2008年9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

Pure alumina monoliths with well-defined macropores and mesostructured skeleton have been synthesized via a spontaneous route from the aqueous and ethanolic solution of aluminum salts in the presence of propylene oxide and high molecular weight poly(ethylene oxide)(PEO). The addition of propylene oxide to the starting solution controls the gelation, while the addition of PEO induces the phase separation. Appropriate choice of the starting composition, with which the phase separation and gelation concur, produces large-dimension (10mm×10mm×10mm), bicontinuous macroporous Al2O 3 monoliths. The mean size of the continuously connected pores is controlled in the micrometer range, depending on the PEO concentration and polarity of the solution. On the other hand, micropores and mesopores, originated from the interstices among primary particles, exhibit median pore size of about 2.6 nm and the BET surface area as high as 396 m2/g after dried temperature at 40°C. © 2007 Materials Research Society.

Web of Science

Scopus

researchmap

Preparation of macroporous poly(divinylbenzene) gels via living radical polymerization 査読有り

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

Materials Research Society Symposium Proceedings 1134 巻頁： 139 - 144 2008年9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

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. © 2009 Materials Research Society.

Web of Science

Scopus

researchmap

Elastic aerogels and xerogels synthesized from methyltrimethoxysilane (MTMS) 査読有り

Kanamori K., Nakanishi K., Hanada T.

Materials Research Society Symposium Proceedings 1134 巻頁： 173 - 178 2008年9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

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. © 2009 Materials Research Society.

Scopus

Multiscale templating of siloxane gels via polymerization-induced phase separation 査読有り

Nakanishi, K; Amatani, T; Yano, S; Kodaira, T

CHEMISTRY OF MATERIALS 20 巻 ( 3 ) 頁： 1108 - 1115 2008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：Chemistry of Materials

By combining the micellar templating in nanometer-scale with the polymerization-induced phase separation in micrometer-scale, we can synthesize monolithic silica or silsesquioxane gel materials with hierarchical well-defined macropores and shape-controlled mesopores. Depending on the mechanism of enhancing micellar-templating of siloxane oligomers, macroframeworks containing long-range-ordered cylindrical mesopores with different degrees of order have been produced. Alkylene-bridged silicon alkoxides can also be prepared into similarly hierarchical porous structures with broadened variations in framework morphology. These examples demonstrate the versatility of using phase-separation in micellartemplated gelling systems to obtain well-defined macroporous structures. © 2008 American Chemical Society.

DOI： 10.1021/cm702486b

Hierarchically porous oxides, hybrids and polymers via sol-gel accompanied by phase separation 査読有り

Nakanishi Kazuki

ORGANIC/INORGANIC HYBRID MATERIALS - 2007 1007 巻頁： 51 - 62 2008年

Phase separation in alkoxy-derived silica system containing polyacrylamide 査読有り

Kawamoto, K; Nakanishi, K; Hanada, T

ORGANIC/INORGANIC HYBRID MATERIALS - 2007 1007 巻頁： 63 - 68 2008年

Phase separation in Al2O3 sol-gel system incorporated with high molecular weight poly(ethylene oxide) 査読有り

Tokudome, Y; Nakanishi, K; Fujita, K; Miura, K; Hirao, K

ORGANIC/INORGANIC HYBRID MATERIALS - 2007 1007 巻頁： 69 - 74 2008年

Sol-gel with phase separation. Hierarchically porous materials optimized for high-performance liquid chromatography separations 査読有り

Nakanishi, K; Tanaka, N

ACCOUNTS OF CHEMICAL RESEARCH 40 巻 ( 9 ) 頁： 863 - 873 2007年9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：Accounts of Chemical Research

Sol-gel processes for fabricating oxides or metalloxane polymers with controlled porous structures have been reviewed. Gel materials having controlled macropores are synthesized by polymerization-induced phase separation and concurrent sol-gel transition in a variety of chemical compositions. Several variations of tailoring mesopore structures within the macroporous materials are introduced, which enable one to design hierarchically porous metal oxide and metalloxane polymer materials. Applications of monolithic silica gels having hierarchical macro/mesoporous structure to the separation media of high-performance liquid chromatography, HPLC, are described. © 2007 American Chemical Society.

DOI： 10.1021/ar600034p

New transparent methylsilsesquioxane aerogels and xerogels with improved mechanical properties 査読有り

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

ADVANCED MATERIALS 19 巻 ( 12 ) 頁： 1589 - + 2007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：Advanced Materials

Transparent hydrophobic MSQ aerogels and aerogel-like xerogels have been obtained from a single trifunctional precursor. Two kinds of surfactants were used to suppress phase separation between the hydrophobic MTMS-derived species and polar solvents. Urea acts as a polymerization accelerator to freeze the structure prior to macroscopic phase separation. Some of the obtained gels showed reversible deformation during uniaxial compression tests and thus were successfully dried by evaporation drying under ambient pressures. The obtained xerogels exhibited similar pore properties to corresponding aerogels such as high porosity and transparency. The new method may lead to lower-cost and larger-scale industrial processes, suggesting that aerogels will find increased usage in general applications such as insulators for windows and solar heat panels.

DOI： 10.1002/adma.200602457

Performance of monolithic silica capillary columns with increased phase ratios and small-sized domains 査読有り

Hara, T; Kobayashi, H; Ikegami, T; Nakanishi, K; Tanaka, N

ANALYTICAL CHEMISTRY 78 巻 ( 22 ) 頁： 7632 - 7642 2006年11月

Living radical polymerization in size-exclusion silica gel column reactors 査読有り

Katsube M., Ouchi M., Ando T., Sawamoto M., Nakanishi K., Ishizuka N.

Polymer Preprints, Japan 55 巻 ( 1 ) 2006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：Polymer Preprints, Japan

This work was aimed to development of continuous-flow living radical polymerization in a silica-gel column, "Chromolith", focusing its separation function by combination of surface chemical absorption and size-exclusion via uniquely shaped mesopores, Thus, living radical copolymerization of two monomers with different polarities, methyl methacrylate (MMA) and 2(dimethylamino)ethyl methacrylate (DMAEMA) was performed with a catalyst [2; Ru(Ind)Cl(PPh3)2] coupled with an initiator (1). Copolymers were continuously produced, and molecular weight distributions were narrower than that in the corresponding batch process.

Scopus

Preparation of novel macroporous polymer monoliths using polymerization-induced phase separation 査読有り

Kanamori K., Nakanishi K.

Polymer Preprints, Japan 55 巻 ( 1 ) 2006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：Polymer Preprints, Japan

Macroporous polymer monoliths with rigid three-dimensional networks have been prepared via living radical polymerization of multi-functional vinyl crosslinkers. By incorporating a polymeric agent to effectively induce phase separation, well-defined macroporous morphology with highly interconnected gel skeletons and macropores has been formed presumably by spinodal decomposition. The pore size and volume are found to be controlled simply by changing starting compositions.

Scopus

Rigid macroporous poly(divinylbenzene) monoliths with a well-defined bicontinuous morphology prepared by living radical polymerization 査読有り

Kanamori, K; Nakanishi, K; Hanada, T

ADVANCED MATERIALS 18 巻 ( 18 ) 頁： 2407 - + 2006年9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：Advanced Materials

Monolithic rigid macroporous poly(divinylbenzene) with well-defined bicontinuous morphology was prepared by living radical polymerization. polydimethylsiloxane (PDMS) was used as a phase separator, and acetic anhydride acted as an acylating agent, resulting in the formation of a coordination bond between the methyl carbon on acetic anhydride and the lone electron pair on the alkoxyamine nitrogen. A bicontinous configuration could be observed with the dimethylsiloxane (DMS)-derived gel skeletons and macropores interconnected to form a 3D network. The study confirmed that heat treatment at 200°C does not have any influence on the macroporous morphology. It was also confirmed that the segregation of highly crosslinked particles could be prevented, and the well-defined bicontinuous structure developed by the initial SD step was preserved at the sub-micrometer scale. This method is expected to be applicable to a variety of living polymerization systems.

DOI： 10.1002/adma.200601026

<中西 和樹>

論文 - 中西 和樹

<中西　和樹>

論文 - 中西　和樹