The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Kenichi Okamoto - One of the best experts on this subject based on the ideXlab platform.
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novel sulfonated Polyimides as polyelectrolytes for fuel cell application 1 synthesis proton conductivity and water stability of Polyimides from 4 4 diaminodiphenyl ether 2 2 disulfonic acid
Macromolecules, 2002Co-Authors: Jianhua Fang, Xiaoxia Guo, Tatsuya Watari, Hidetoshi Kita, Satoshi Harada, Kazuhiro Tanaka, Kenichi OkamotoAbstract:A sulfonated diamine monomer, 4,4‘-diaminodiphenyl ether-2,2‘-disulfonic acid (ODADS), was successfully synthesized by direct sulfonation of a commercially available diamine, 4,4‘-diaminodiphenyl ether (ODA), using fuming sulfuric acid as the sulfonating reagent. A series of sulfonated Polyimides were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), ODADS, and common nonsulfonated diamines. The resulting sulfonated Polyimides displayed much better stability toward water than those derived from the widely used sulfonated diamine 2,2‘-benzidinedisulfonic acid (BDSA). This is because ODADS-based polyimide membranes have a more flexible structure than the corresponding BDSA-based ones. Fenton's reagent test revealed that ODADS-based polyimide membranes also had fair good stability to oxidation. Polyimide membranes with good water stability as well as high proton conductivity were developed. NTDA−ODADS/BAPB(1/1) copolyimide membrane (BAPB refers to 4,4‘-bis(4-aminophenoxy)biphenyl)), for ex...
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novel sulfonated Polyimides as polyelectrolytes for fuel cell application 2 synthesis and proton conductivity of Polyimides from 9 9 bis 4 aminophenyl fluorene 2 7 disulfonic acid
Macromolecules, 2002Co-Authors: Xiaoxia Guo, Tatsuya Watari, Hidetoshi Kita, Jianhua Fang, Kazuhiro Tanaka, Kenichi OkamotoAbstract:A new sulfonated diamine monomer, 9,9-bis(4-aminophenyl)fluorene-2,7-disulfonic acid (BAPFDS), was synthesized by direct sulfonation of the parent diamine, 9,9-bis(4-aminophenyl)fluorene (BAPF), using fuming sulfuric acid as the sulfonating reagent. A series of sulfonated Polyimides with different sulfonation degrees were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), BAPFDS, and common nonsulfonated diamines. The resulting sulfonated Polyimides generally showed good solubility in m-cresol and DMSO. Proton conductivities of these polyimide membranes were measured as the functions of relative humidity and temperature. The resulting homopolyimide, NTDA-BAPFDS, displayed proton conductivities quite similar to those of Nafion 117 in the whole humidity range (RH < 100%). At 100% relative humidity, all the BAPFDS-based polyimide membranes showed proton conductivities similar to or higher than those of Nafion 117. In addition, BAPFDS-based polyimide membranes exhibited much better water sta...
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permeability and permselectivity of gases in fluorinated and non fluorinated Polyimides
Polymer, 1992Co-Authors: Kazuhiro Tanaka, Hidetoshi Kita, Masaaki Okano, Kenichi OkamotoAbstract:Abstract Solubility and permeability coefficients for gases in a series of fluorinated and non-fluorinated Polyimides were measured to investigate the effects of chemical structure on permeability and permselectivity. Polyimides with higher concentration of fluorine had lower chain packing density and higher permeability. Polyimides with C(CF3)2 linkages had higher permeability with relatively higher permselectivity. 2,2-Bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride/2,2-bis(4-aminophenyl)hexafluoropropane (6FDA-BAHF) polyimide with two C(CF3)2 linkages in the polymer repeat unit displayed excellent performance for CO 2 CH 4 and O 2 N 2 separations; its permeabilities for O2 and CO2 were 3.7 and 3.1 times, respectively, larger than those of 6FDA-pp′ODA (4,4′-oxydianiline), a conventional 6FDA-based polyimide, while the permselectivities for O 2 N 2 and CO 2 CH 4 were 13% and 22%, respectively, smaller. On the other hand, Polyimides having two C(CF3)2 linkages together with two ether ones in the repeat unit had lower permeability with a similar level of permselectivity as compared with 6FDA-BAHF polyimide. For H 2 CH 4 and H 2 CO separations, Polyimides prepared from 6FDA and meta-oriented non-fluorinated diamines were preferable. These separation properties were discussed in connection with packing density and local segmental mobility.
Kazuhiro Tanaka - One of the best experts on this subject based on the ideXlab platform.
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novel sulfonated Polyimides as polyelectrolytes for fuel cell application 1 synthesis proton conductivity and water stability of Polyimides from 4 4 diaminodiphenyl ether 2 2 disulfonic acid
Macromolecules, 2002Co-Authors: Jianhua Fang, Xiaoxia Guo, Tatsuya Watari, Hidetoshi Kita, Satoshi Harada, Kazuhiro Tanaka, Kenichi OkamotoAbstract:A sulfonated diamine monomer, 4,4‘-diaminodiphenyl ether-2,2‘-disulfonic acid (ODADS), was successfully synthesized by direct sulfonation of a commercially available diamine, 4,4‘-diaminodiphenyl ether (ODA), using fuming sulfuric acid as the sulfonating reagent. A series of sulfonated Polyimides were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), ODADS, and common nonsulfonated diamines. The resulting sulfonated Polyimides displayed much better stability toward water than those derived from the widely used sulfonated diamine 2,2‘-benzidinedisulfonic acid (BDSA). This is because ODADS-based polyimide membranes have a more flexible structure than the corresponding BDSA-based ones. Fenton's reagent test revealed that ODADS-based polyimide membranes also had fair good stability to oxidation. Polyimide membranes with good water stability as well as high proton conductivity were developed. NTDA−ODADS/BAPB(1/1) copolyimide membrane (BAPB refers to 4,4‘-bis(4-aminophenoxy)biphenyl)), for ex...
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novel sulfonated Polyimides as polyelectrolytes for fuel cell application 2 synthesis and proton conductivity of Polyimides from 9 9 bis 4 aminophenyl fluorene 2 7 disulfonic acid
Macromolecules, 2002Co-Authors: Xiaoxia Guo, Tatsuya Watari, Hidetoshi Kita, Jianhua Fang, Kazuhiro Tanaka, Kenichi OkamotoAbstract:A new sulfonated diamine monomer, 9,9-bis(4-aminophenyl)fluorene-2,7-disulfonic acid (BAPFDS), was synthesized by direct sulfonation of the parent diamine, 9,9-bis(4-aminophenyl)fluorene (BAPF), using fuming sulfuric acid as the sulfonating reagent. A series of sulfonated Polyimides with different sulfonation degrees were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), BAPFDS, and common nonsulfonated diamines. The resulting sulfonated Polyimides generally showed good solubility in m-cresol and DMSO. Proton conductivities of these polyimide membranes were measured as the functions of relative humidity and temperature. The resulting homopolyimide, NTDA-BAPFDS, displayed proton conductivities quite similar to those of Nafion 117 in the whole humidity range (RH < 100%). At 100% relative humidity, all the BAPFDS-based polyimide membranes showed proton conductivities similar to or higher than those of Nafion 117. In addition, BAPFDS-based polyimide membranes exhibited much better water sta...
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permeability and permselectivity of gases in fluorinated and non fluorinated Polyimides
Polymer, 1992Co-Authors: Kazuhiro Tanaka, Hidetoshi Kita, Masaaki Okano, Kenichi OkamotoAbstract:Abstract Solubility and permeability coefficients for gases in a series of fluorinated and non-fluorinated Polyimides were measured to investigate the effects of chemical structure on permeability and permselectivity. Polyimides with higher concentration of fluorine had lower chain packing density and higher permeability. Polyimides with C(CF3)2 linkages had higher permeability with relatively higher permselectivity. 2,2-Bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride/2,2-bis(4-aminophenyl)hexafluoropropane (6FDA-BAHF) polyimide with two C(CF3)2 linkages in the polymer repeat unit displayed excellent performance for CO 2 CH 4 and O 2 N 2 separations; its permeabilities for O2 and CO2 were 3.7 and 3.1 times, respectively, larger than those of 6FDA-pp′ODA (4,4′-oxydianiline), a conventional 6FDA-based polyimide, while the permselectivities for O 2 N 2 and CO 2 CH 4 were 13% and 22%, respectively, smaller. On the other hand, Polyimides having two C(CF3)2 linkages together with two ether ones in the repeat unit had lower permeability with a similar level of permselectivity as compared with 6FDA-BAHF polyimide. For H 2 CH 4 and H 2 CO separations, Polyimides prepared from 6FDA and meta-oriented non-fluorinated diamines were preferable. These separation properties were discussed in connection with packing density and local segmental mobility.
Hidetoshi Kita - One of the best experts on this subject based on the ideXlab platform.
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novel sulfonated Polyimides as polyelectrolytes for fuel cell application 1 synthesis proton conductivity and water stability of Polyimides from 4 4 diaminodiphenyl ether 2 2 disulfonic acid
Macromolecules, 2002Co-Authors: Jianhua Fang, Xiaoxia Guo, Tatsuya Watari, Hidetoshi Kita, Satoshi Harada, Kazuhiro Tanaka, Kenichi OkamotoAbstract:A sulfonated diamine monomer, 4,4‘-diaminodiphenyl ether-2,2‘-disulfonic acid (ODADS), was successfully synthesized by direct sulfonation of a commercially available diamine, 4,4‘-diaminodiphenyl ether (ODA), using fuming sulfuric acid as the sulfonating reagent. A series of sulfonated Polyimides were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), ODADS, and common nonsulfonated diamines. The resulting sulfonated Polyimides displayed much better stability toward water than those derived from the widely used sulfonated diamine 2,2‘-benzidinedisulfonic acid (BDSA). This is because ODADS-based polyimide membranes have a more flexible structure than the corresponding BDSA-based ones. Fenton's reagent test revealed that ODADS-based polyimide membranes also had fair good stability to oxidation. Polyimide membranes with good water stability as well as high proton conductivity were developed. NTDA−ODADS/BAPB(1/1) copolyimide membrane (BAPB refers to 4,4‘-bis(4-aminophenoxy)biphenyl)), for ex...
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novel sulfonated Polyimides as polyelectrolytes for fuel cell application 2 synthesis and proton conductivity of Polyimides from 9 9 bis 4 aminophenyl fluorene 2 7 disulfonic acid
Macromolecules, 2002Co-Authors: Xiaoxia Guo, Tatsuya Watari, Hidetoshi Kita, Jianhua Fang, Kazuhiro Tanaka, Kenichi OkamotoAbstract:A new sulfonated diamine monomer, 9,9-bis(4-aminophenyl)fluorene-2,7-disulfonic acid (BAPFDS), was synthesized by direct sulfonation of the parent diamine, 9,9-bis(4-aminophenyl)fluorene (BAPF), using fuming sulfuric acid as the sulfonating reagent. A series of sulfonated Polyimides with different sulfonation degrees were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), BAPFDS, and common nonsulfonated diamines. The resulting sulfonated Polyimides generally showed good solubility in m-cresol and DMSO. Proton conductivities of these polyimide membranes were measured as the functions of relative humidity and temperature. The resulting homopolyimide, NTDA-BAPFDS, displayed proton conductivities quite similar to those of Nafion 117 in the whole humidity range (RH < 100%). At 100% relative humidity, all the BAPFDS-based polyimide membranes showed proton conductivities similar to or higher than those of Nafion 117. In addition, BAPFDS-based polyimide membranes exhibited much better water sta...
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permeability and permselectivity of gases in fluorinated and non fluorinated Polyimides
Polymer, 1992Co-Authors: Kazuhiro Tanaka, Hidetoshi Kita, Masaaki Okano, Kenichi OkamotoAbstract:Abstract Solubility and permeability coefficients for gases in a series of fluorinated and non-fluorinated Polyimides were measured to investigate the effects of chemical structure on permeability and permselectivity. Polyimides with higher concentration of fluorine had lower chain packing density and higher permeability. Polyimides with C(CF3)2 linkages had higher permeability with relatively higher permselectivity. 2,2-Bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride/2,2-bis(4-aminophenyl)hexafluoropropane (6FDA-BAHF) polyimide with two C(CF3)2 linkages in the polymer repeat unit displayed excellent performance for CO 2 CH 4 and O 2 N 2 separations; its permeabilities for O2 and CO2 were 3.7 and 3.1 times, respectively, larger than those of 6FDA-pp′ODA (4,4′-oxydianiline), a conventional 6FDA-based polyimide, while the permselectivities for O 2 N 2 and CO 2 CH 4 were 13% and 22%, respectively, smaller. On the other hand, Polyimides having two C(CF3)2 linkages together with two ether ones in the repeat unit had lower permeability with a similar level of permselectivity as compared with 6FDA-BAHF polyimide. For H 2 CH 4 and H 2 CO separations, Polyimides prepared from 6FDA and meta-oriented non-fluorinated diamines were preferable. These separation properties were discussed in connection with packing density and local segmental mobility.
Jianhua Fang - One of the best experts on this subject based on the ideXlab platform.
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novel sulfonated Polyimides as polyelectrolytes for fuel cell application 1 synthesis proton conductivity and water stability of Polyimides from 4 4 diaminodiphenyl ether 2 2 disulfonic acid
Macromolecules, 2002Co-Authors: Jianhua Fang, Xiaoxia Guo, Tatsuya Watari, Hidetoshi Kita, Satoshi Harada, Kazuhiro Tanaka, Kenichi OkamotoAbstract:A sulfonated diamine monomer, 4,4‘-diaminodiphenyl ether-2,2‘-disulfonic acid (ODADS), was successfully synthesized by direct sulfonation of a commercially available diamine, 4,4‘-diaminodiphenyl ether (ODA), using fuming sulfuric acid as the sulfonating reagent. A series of sulfonated Polyimides were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), ODADS, and common nonsulfonated diamines. The resulting sulfonated Polyimides displayed much better stability toward water than those derived from the widely used sulfonated diamine 2,2‘-benzidinedisulfonic acid (BDSA). This is because ODADS-based polyimide membranes have a more flexible structure than the corresponding BDSA-based ones. Fenton's reagent test revealed that ODADS-based polyimide membranes also had fair good stability to oxidation. Polyimide membranes with good water stability as well as high proton conductivity were developed. NTDA−ODADS/BAPB(1/1) copolyimide membrane (BAPB refers to 4,4‘-bis(4-aminophenoxy)biphenyl)), for ex...
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novel sulfonated Polyimides as polyelectrolytes for fuel cell application 2 synthesis and proton conductivity of Polyimides from 9 9 bis 4 aminophenyl fluorene 2 7 disulfonic acid
Macromolecules, 2002Co-Authors: Xiaoxia Guo, Tatsuya Watari, Hidetoshi Kita, Jianhua Fang, Kazuhiro Tanaka, Kenichi OkamotoAbstract:A new sulfonated diamine monomer, 9,9-bis(4-aminophenyl)fluorene-2,7-disulfonic acid (BAPFDS), was synthesized by direct sulfonation of the parent diamine, 9,9-bis(4-aminophenyl)fluorene (BAPF), using fuming sulfuric acid as the sulfonating reagent. A series of sulfonated Polyimides with different sulfonation degrees were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), BAPFDS, and common nonsulfonated diamines. The resulting sulfonated Polyimides generally showed good solubility in m-cresol and DMSO. Proton conductivities of these polyimide membranes were measured as the functions of relative humidity and temperature. The resulting homopolyimide, NTDA-BAPFDS, displayed proton conductivities quite similar to those of Nafion 117 in the whole humidity range (RH < 100%). At 100% relative humidity, all the BAPFDS-based polyimide membranes showed proton conductivities similar to or higher than those of Nafion 117. In addition, BAPFDS-based polyimide membranes exhibited much better water sta...
Xiaoxia Guo - One of the best experts on this subject based on the ideXlab platform.
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novel sulfonated Polyimides as polyelectrolytes for fuel cell application 1 synthesis proton conductivity and water stability of Polyimides from 4 4 diaminodiphenyl ether 2 2 disulfonic acid
Macromolecules, 2002Co-Authors: Jianhua Fang, Xiaoxia Guo, Tatsuya Watari, Hidetoshi Kita, Satoshi Harada, Kazuhiro Tanaka, Kenichi OkamotoAbstract:A sulfonated diamine monomer, 4,4‘-diaminodiphenyl ether-2,2‘-disulfonic acid (ODADS), was successfully synthesized by direct sulfonation of a commercially available diamine, 4,4‘-diaminodiphenyl ether (ODA), using fuming sulfuric acid as the sulfonating reagent. A series of sulfonated Polyimides were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), ODADS, and common nonsulfonated diamines. The resulting sulfonated Polyimides displayed much better stability toward water than those derived from the widely used sulfonated diamine 2,2‘-benzidinedisulfonic acid (BDSA). This is because ODADS-based polyimide membranes have a more flexible structure than the corresponding BDSA-based ones. Fenton's reagent test revealed that ODADS-based polyimide membranes also had fair good stability to oxidation. Polyimide membranes with good water stability as well as high proton conductivity were developed. NTDA−ODADS/BAPB(1/1) copolyimide membrane (BAPB refers to 4,4‘-bis(4-aminophenoxy)biphenyl)), for ex...
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novel sulfonated Polyimides as polyelectrolytes for fuel cell application 2 synthesis and proton conductivity of Polyimides from 9 9 bis 4 aminophenyl fluorene 2 7 disulfonic acid
Macromolecules, 2002Co-Authors: Xiaoxia Guo, Tatsuya Watari, Hidetoshi Kita, Jianhua Fang, Kazuhiro Tanaka, Kenichi OkamotoAbstract:A new sulfonated diamine monomer, 9,9-bis(4-aminophenyl)fluorene-2,7-disulfonic acid (BAPFDS), was synthesized by direct sulfonation of the parent diamine, 9,9-bis(4-aminophenyl)fluorene (BAPF), using fuming sulfuric acid as the sulfonating reagent. A series of sulfonated Polyimides with different sulfonation degrees were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), BAPFDS, and common nonsulfonated diamines. The resulting sulfonated Polyimides generally showed good solubility in m-cresol and DMSO. Proton conductivities of these polyimide membranes were measured as the functions of relative humidity and temperature. The resulting homopolyimide, NTDA-BAPFDS, displayed proton conductivities quite similar to those of Nafion 117 in the whole humidity range (RH < 100%). At 100% relative humidity, all the BAPFDS-based polyimide membranes showed proton conductivities similar to or higher than those of Nafion 117. In addition, BAPFDS-based polyimide membranes exhibited much better water sta...