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Iwai, Yasunori; Yamanishi, Toshihiko; Isobe, Kanetsugu; Nishi, Masataka; Yagi, Toshiaki; Tamada, Masao
Fusion Engineering and Design, 81(1-7), p.815 - 820, 2006/02
Times Cited Count：15 Percentile：70.56(Nuclear Science & Technology)Solid-polymer-electrolyte (SPE) water electrolysis is attractive in electrolytic process of water detritiation system (WDS) in fusion reactors because it can electrolyze liquid waste directly, but radioactive durability of its ion exchange membrane is a key point. Radioactive durability of Nafion, a typical commercial ion exchange membrane, was experimentally investigated using Co-60 irradiation facility and electron beam irradiation facility at Takasaki Radiation Chemistry Research Establishment of JAERI. Nafion is composed of PTFE (Polytetrafluoroethylene) main chain. However the degradation of its mechanical strength by irradiation was significantly distinguished from that of PTFE and no serious damage was observed for its ion exchange capacity up to 530 kGy, the requirement of ITER. Atmospheric effects such as soaking and oxygen on degrading behaviors were discussed from the viewpoint of radical reaction mechanism. Dependencies of operating temperature and radioactive source are also demonstrated in detail.
Sawada, Shinichi; Yamaki, Tetsuya; Asano, Masaharu; Terai, Takayuki*; Yoshida, Masaru
Transactions of the Materials Research Society of Japan, 30(4), p.943 - 946, 2005/12
We synthesized crosslinked-polytetrafluoroethylene (PTFE) electrolyte membranes by a radiation grafting technique under different conditions, and then investigated their proton conduction properties at controlled temperatures and relative humidities (R.H.) by an AC impedance method. The density and length of graft chains were controlled by varying the pre-irradiation dose and grafting time, respectively. When the pre-irradiation dose was fixed at 15 kGy to make the graft chains an uniform density, the elongation of the graft chain increased the ion exchange capacity (IEC), there by enhancing their proton conductivity. The membrane with an IEC of 2.8 meq/g possessed the maximum conductivity reaching 0.20 S/cm at 80 
C and R.H. 95%. At almost the same IEC, membranes with more and shorter graft chains showed higher conductivity than those with less and longer chains. This result was probably related to the different structures of hydrophilic domains as proton-conducting pathways.
Yamaki, Tetsuya; Asano, Masaharu; Yoshida, Masaru
Gekkan Eko Indasutori, 10(6), p.5 - 11, 2005/06
no abstracts in English
Yamaki, Tetsuya; Asano, Masaharu; Yoshida, Masaru
Kogyo Zairyo, 53(1), p.63 - 67, 2005/01
no abstracts in English
Yamaki, Tetsuya; Yoshida, Masaru
Nenryo Denchi, 4(3), p.73 - 78, 2005/01
no abstracts in English
Udagawa, Akira*; Ikeda, Shigetoshi*; Yagi, Toshiaki
Hoshasen To Sangyo, (103), p.54 - 58, 2004/09
no abstracts in English
Yamaki, Tetsuya; Asano, Masaharu; Yoshida, Masaru
Kogyo Zairyo, 51(4), p.39 - 42, 2003/04
no abstracts in English
Sato, Yasunori*; Yamaguchi, Daichi*; Oshima, Akihiro*; Kato, Takanori*; Ikeda, Shigetoshi*; Aoki, Yasushi*; Tanaka, Shigeru; Tabata, Yoneho*; Washio, Masakazu*
JAERI-Conf 2003-001, p.245 - 250, 2003/03
no abstracts in English
Inoue, Yutaka; Kobayashi, Kazuhiro; Yamaki, Tetsuya; Asano, Masaharu; Kubota, Hitoshi*; Yoshida, Masaru
Dai-2-Kai 21-Seiki Rengo Shimpojiumu; Kagaku Gijutsu To Ningen Rombunshu, p.257 - 260, 2003/00
We prepared crosslinked fluoropolymer electrolyte membranes for use in fuel cells and then investigated their structural properties by X-ray diffraction (XRD) analysis. The radiation-induced grafting of styrene into crosslinked polytetrafluoroethylene (PTFE) films and subsequent sulfonation enabled us to obtain the electrolyte membrane with a sufficient ion exchange capacity, which exceeds that of the commercially-available film, Nafion. As the crosslinking and styrene grafting reactions proceeded, the size of the PTFE crystallites in the film became smaller, thereby decreasing the film crystallinity. Interestingly, in contrast to Nafion, the resulting sulfonated membranes were found to have high crystallinity.
Yamaki, Tetsuya; Asano, Masaharu; Morita, Yosuke*; Suwa, Takeshi*; Yoshida, Masaru
Proceedings of 9th International Conference on Radiation Curing (RadTech Asia '03) (CD-ROM), 4 Pages, 2003/00
Proton exchange membranes were prepared by the radiation-induced grafting of styrene into crosslinked polytetrafluoroethylene (PTFE) films and subsequent sulfonation. The degree of grafting was controlled in the range of 7-75% by the crosslinking density of the PTFE matrix as well as the grafting conditions. The films at the grafting yield of 
30% were found to give the ion exchange membranes with a homogeneous distribution of sulfonic acid groups. The resulting membranes showed a large ion exchange capacity reaching 2.9 meq g
, which exceeded the performance of commercially-available perfluorosulfonic acid films such as Nafion. This will encourage the use of our ion exchange membranes in polymer electrolyte fuel cells.
Yoshida, Masaru; Yamaki, Tetsuya
Saishin Nenryo Denchi Buzai; Sono Saisentan Gijutsu To Shinraisei Hyoka, p.82 - 92, 2003/00
no abstracts in English
Yamaki, Tetsuya; Yoshida, Masaru
Zukai, Nenryo Denchi no Subete, p.117 - 119, 2003/00
no abstracts in English
Suwa, Takeshi
Porima Daijesuto, 54(3), p.17 - 26, 2002/03
no abstracts in English
Oshima, Akihiro; Udagawa, Akira; Morita, Yosuke
Radiation Physics and Chemistry, 60(4-5), p.467 - 471, 2001/03
Times Cited Count：12 Percentile：64.73(Chemistry, Physical)Plain-woven carbon fber-filled polytetrafluoroethylene (PTFE)composites were fabricated by radiation-crosslinking under selective conditions.High mechanical and frictional properties are found in the composite materials compared with crosslinked PTFE without fiber.The composite materials with optional shapes,which are laminated after electron beam (EB) crosslinking treatment of each mono-layer could also be fabricated.
Oshima, Akihiro; Udagawa, Akira; Morita, Yosuke
Radiation Physics and Chemistry, 60(1-2), p.95 - 100, 2001/01
Times Cited Count：8 Percentile：52.36(Chemistry, Physical)no abstracts in English
Oshima, Akihiro; Udagawa, Akira; Morita, Yosuke
Proceedings of International Symposium on Prospect for Application of Radiation towards the 21st Century, p.83 - 84, 2000/00
no abstracts in English
Seguchi, Tadao
Radiation Physics and Chemistry, 57, p.367 - 371, 2000/00
Times Cited Count：29 Percentile：85.04(Chemistry, Physical)no abstracts in English
*; Udagawa, Akira; Morita, Yosuke
Conference Proceeding RadTech Asia'99, p.507 - 512, 1999/08
no abstracts in English
*; Udagawa, Akira; Morita, Yosuke
JAERI-Tech 99-012, 15 Pages, 1999/02
no abstracts in English
Co 
-raysIkeda, Shigetoshi*; Kasai, Noboru; *; *; Haruyama, Yasuyuki; Seguchi, Tadao
JAERI-Tech 99-005, 37 Pages, 1999/02
no abstracts in English
