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Asano, Masaharu; Chen, J.; Maekawa, Yasunari; Sakamura, Takahiro*; Kubota, Hitoshi*; Yoshida, Masaru
Journal of Polymer Science, Part A; Polymer Chemistry, 45(13), p.2624 - 2637, 2007/07
A novel process comprising UV-induced photografting of styrene into polytetrafluoroethylene (PTFE) films and subsequent sulfonation has been developed for preparing proton-conducting membranes. The significance of this process is that the polystyrene can graft throughout the PTFE films. Even through the degree of grafting was lower than 10 %, the proton conductivity of the newly prepared membranes can reach a value similar to Nafion. In comparison with 
-ray radiation grafting, UV photografting is less damaging to the membranes because significant degradation of the PTFE main chains can be avoided.
Chen, J.; Asano, Masaharu; Maekawa, Yasunari; Sakamura, Takahiro*; Kubota, Hitoshi*; Yoshida, Masaru
Journal of Membrane Science, 283(1-2), p.373 - 379, 2006/10
Times Cited Count：23 Percentile：58.34(Engineering, Chemical)A novel process comprising UV-induced photografting of styrene into poly(tetrafluoroethylene-co-ethylene) (ETFE) films in vapor and liquid phases, followed by electron beam-induced crosslinking has been developed for preparing polymer electrolyte membranes. The significance of this process is that the photografted polystyrene chains can completely penetrate into the base ETFE film; the membranes show proton conductibility available for fuel cell applications. On one hand, the proton conductivity of the liquid-phase photografted electrolyte membranes is higher than the vapor-phase one, and is anisotropic in the surface and thickness directions. On the other hand, radiation-induced crosslinking greatly improves the chemical stability of the resultant fuel cell membranes, and maintains the surface concentration of sulfonic acid groups at its higher level.
Chen, J.; Asano, Masaharu; Maekawa, Yasunari; Sakamura, Takahiro*; Kubota, Hitoshi*; Yoshida, Masaru
Electrochemical and Solid-State Letters, 9(11), p.G326 - G329, 2006/00
Times Cited Count：5 Percentile：21.90(Electrochemistry)A novel process comprising UV-induced photografting of styrene into PTFE films and subsequent sulfonation has been developed for preparing proton-conducting membranes. The significance of this process is that the graft chains can penetrate throughout the PTFE base films; the resultant sulfonated electrolyte membrane with a low degree of grafting near 7% shows higher proton conductibility and better mechanical properties, similar to those of Nafion membrane. Furthermore, the performances of the UV-photografted electrolyte membranes are better as compared to those of the radiation grafted electrolyte membranes.
Chen, J.; Asano, Masaharu; Maekawa, Yasunari; Sakamura, Takahiro*; Kubota, Hitoshi*; Yoshida, Masaru
Electrochemical and Solid-State Letters, 9(5), p.G184 - G186, 2006/00
Times Cited Count：8 Percentile：31.00(Electrochemistry)UV radiation-induced photografting of styrene into ETFE films for the preparation of fuel cell membranes was carried out. The proton conductivity in thickness direction of membranes prepared by the vapor- and liquid-phase photografting can reach as high as 0.065 and 0.087 S/cm, respectively. The higher conductivity in the liquid-phase grafting is close to the homogeneity of graft chain distribution in the membrane.
Asano, Masaharu; Chen, J.; Maekawa, Yasunari; Yoshida, Masaru; Sakamura, Takahiro*; Kubota, Hitoshi*
no journal, ,
no abstracts in English
Sakamura, Takahiro*; Kuroda, Shinichi*; Kubota, Hitoshi*; Chen, J.; Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru
no journal, ,
UV radiation-induced photografting of styrene into ETFE films for the preparation of fuel cell membranes was carried out. The proton conductivity in thickness direction of membranes prepared by the vapor- and liquid-phase photografting can reach as high as 0.036 and 0.072 S/cm, respectively. The higher conductivity in the liquid-phase grafting is close to the homogeneity of graft chain distribution in the membrane.
Sakamura, Takahiro*; Kuroda, Shinichi*; Kubota, Hitoshi*; Asano, Masaharu; Chen, J.; Maekawa, Yasunari; Yoshida, Masaru
no journal, ,
no abstracts in English
Yoshida, Masaru; Asano, Masaharu; Chen, J.; Maekawa, Yasunari; Sakamura, Takahiro*; Kubota, Hitoshi*
no journal, ,
no abstracts in English
