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Zhao, Y.; Yoshimura, Kimio; Shishitani, Hideyuki*; Yamaguchi, Susumu*; Tanaka, Hirohisa*; Koizumi, Satoshi*; Szekely, N.*; Radulescu, A.*; Richter, D.*; Maekawa, Yasunari
Soft Matter, 12(5), p.1567 - 1578, 2016/02
Times Cited Count：30 Percentile：79.55(Chemistry, Physical)
-tetrafluoroethylene) films using different mediaNuryanthi, N.*; Yamaki, Tetsuya; Kitamura, Akane; Koshikawa, Hiroshi; Yoshimura, Kimio; Sawada, Shinichi; Hasegawa, Shin; Asano, Masaharu; Maekawa, Yasunari; Suzuki, Akihiro*; et al.
Transactions of the Materials Research Society of Japan, 40(4), p.359 - 362, 2015/12
The ion-track grafting of a vinylbenzyl chloride (VBC) into a poly(ethylene-co-tetrafluoroethylene) (ETFE) film is necessary for preparing nanostructured hydroxide-ion-conductive electrolyte membranes. A key for success here is to obtain as high graft levels as possible (for higher conductivity) in a smaller number of tracks (for improving the other membrane properties). To this end, therefore, the effect of the medium for the VBC grafting was investigated as part of our continuing effort to optimize the experimental conditions. A 25 
m-thick ETFE film was irradiated in a vacuum chamber with 560 MeV 
Xe at different fluences, and then the grafting was performed by immersing the irradiated films in a 20vol% VBC monomer at 60
C. A medium was a mixture of water (H
O) and isopropyl alcohol (iPrOH) at different volume ratios. The degree of grafting increased as the HO content became higher, and reached a maximum in pure HO. These results can be explained by considering the well-known Trommsdorff effect, in which poor solubility of the grafted polymer in polar media leads to an increased polymerization rate probably due to a lower termination rate.
Yoshimura, Kimio; Koshikawa, Hiroshi; Yamaki, Tetsuya; Shishitani, Hideyuki*; Yamamoto, Kazuya*; Yamaguchi, Susumu*; Tanaka, Hirohisa*; Maekawa, Yasunari
Journal of the Electrochemical Society, 161(9), p.F889 - F893, 2014/06
Times Cited Count：23 Percentile：60.51(Electrochemistry)Graft-type anion-conducting electrolyte membranes (AEMs) with imidazolium cations on graft polymers were synthesized through radiation-induced graft polymerization of 
-vinylimidazole (NVIm) on poly(ethylene-co-tetrafluoroethylene) (ETFE) films, followed by -propylation and ion-exchange reactions. The -propylation proceeded quantitatively, whereas the ion-exchange reactions in 1 M KOH at 60C were accompanied by partial 
-elimination of the imidazolium cations(AEM2), which exhibited an ion-exchange capacity (IEC) of 0.85 mmol g
and ionic conductivity of 10 mS cm. AEM2 showed alkaline stability at 60C but it gradually degraded at 80C for ca. 150 h. The copolymer-type AEM (AEM3) with an IEC of 1.20 mmol g was prepared through the copolymerization of NVIm with styrene on ETFE films, followed by the same -propylation and ion-exchange reactions. AEM3 was shown higher alkaline durability in 1 M KOH at 80C. As a result, it exhibited higher conductivity (
10 mS cm) for 250 h. Therefore, alkylimidazolium cations in copolymer grafts are a promising anion conducting group for alkaline-durable AEMs. A maximum power density of 75 mW cm
is obtained for AEM3 in a direct hydrazine hydrate fuel cell.
Tran Duy, T.*; Sawada, Shinichi; Hasegawa, Shin; Yoshimura, Kimio; Oba, Yojiro*; Onuma, Masato*; Katsumura, Yosuke*; Maekawa, Yasunari
Macromolecules, 47(7), p.2373 - 2383, 2014/04
Times Cited Count：34 Percentile：72.65(Polymer Science)The hierarchical structures of graft-type ETFE-based polymer electrolyte membranes (ETFE-PEMs) were investigated using small- and ultrasmall-angle X-ray cattering experiments. The ETFE-PEMs with IECs 
2.4 mmol/g possessed conducting graft domains around lamellar crystals, with a d-spacing of 21.8-29.1 nm, and oriented crystallites with short and long correlation distances of 218-320 and 903-1124 nm, respectively. The membranes with IECs 2.7 mmol/g showed a new phase of crystallite network domains with a d-range of 225-256 nm, indicating a phase transition from oriented crystallite to crystallite network structures in the IEC range of 2.4-2.7 mmol/g. Noted that for the ETFE-PEMs with high IECs higher conductivity at 30% RH and compatible tensile strengths at 100% RH and 80 C, compared with Nafion, originated from the well-interconnected ion channels around the crystallites and the remaining lamellar crystals and crystallites, respectively.
Koshikawa, Hiroshi; Yoshimura, Kimio; Sinnananchi, W.; Yamaki, Tetsuya; Asano, Masaharu; Yamamoto, Kazuya*; Yamaguchi, Susumu*; Tanaka, Hirohisa*; Maekawa, Yasunari
Macromolecular Chemistry and Physics, 214(15), p.1756 - 1762, 2013/08
Times Cited Count：17 Percentile：46.62(Polymer Science)Graft-type anion-conducting polymer electrolyte membranes were prepared by the radiation-induced graft polymerization of chloromethylstyrene into poly(ethylene-co-tetrafluoroethylene) (ETFE) films and subsequent quaternization with trimethylamine to evaluate the counter anion effects on fuel cell properties. The hydroxide form was maintained in -saturated water to prevent the bicarbonate formation. The hydroxide form showed conductivity and water uptake four and two times higher than the chloride and bicarbonate forms. The hydroxide form is thermally and chemically less stable, resulting in the tendency to absorb water and to convert to the bicarbonate form.
Yoshimura, Kimio; Koshikawa, Hiroshi; Yamaki, Tetsuya; Maekawa, Yasunari; Yamamoto, Kazuya*; Shishitani, Hideyuki*; Asazawa, Koichiro*; Yamaguchi, Susumu*; Tanaka, Hirohisa*
ECS Transactions, 50(2), p.2075 - 2081, 2012/10
no abstracts in English
Yoshimura, Kimio; Hakoda, Teruyuki; Yamamoto, Shunya; Yoshikawa, Masahito
Journal of Physics and Chemistry of Solids, 73(5), p.696 - 698, 2012/05
Times Cited Count：4 Percentile：18.77(Chemistry, Multidisciplinary)Tungsten trioxide powder with loading 0.1wt% platinum (Pt/WO
) was prepared for opticaldetection of organic hydrides such as cyclohexane, decalin by impregnation with PtCl
and subsequent calcination in N gas at 500C. The SEM observation of Pt/WO shows that the Pt particles with mean diameters of 80-100 nm were on the surface of the WO powder. The Pt/WO showed coloration for 13% cyclohexane at higher 100C and for 1.3% cyclohexane at 200C. The in-situ XRD results of the Pt/WO in coloring/bleaching change indicate that the coloring of Pt/WO was caused by transformation of WO to tungsten bronze. The analysis of reacted gas demonstrates that Pt on WO produces only hydrogen and benzene through dehydrogenation of cyclohexane over 100C. It was founded that the Pt/WO has potential of optical detection of organic hydrides by heating at higher 100C.
Yoshimura, Kimio; Hakoda, Teruyuki; Sugimoto, Masaki; Yamamoto, Shunya; Yoshikawa, Masahito
Radiation Physics and Chemistry, 80(4), p.587 - 590, 2011/04
Times Cited Count：2 Percentile：17.22(Chemistry, Physical)no abstracts in English
Yoshimura, Kimio; Hakoda, Teruyuki; Yamamoto, Shunya; Yoshikawa, Masahito
Applied Surface Science, 257(9), p.4428 - 4431, 2011/02
Times Cited Count：5 Percentile：23.57(Chemistry, Physical)no abstracts in English
Yoshimura, Kimio; Sinnananchi, W.; Koshikawa, Hiroshi; Yamaki, Tetsuya; Maekawa, Yasunari; Yamamoto, Kazuya*; Shishitani, Hideyuki*; Asazawa, Koichiro*; Yamaguchi, Susumu*; Tanaka, Hirohisa*
no journal, ,
no abstracts in English
substrateKawaguchi, Kazuhiro; Takahiro, Katsumi*; Yamamoto, Shunya; Hakoda, Teruyuki; Yoshimura, Kimio; Yoshikawa, Masahito
no journal, ,
no abstracts in English
Yamamoto, Shunya; Hakoda, Teruyuki; Kawaguchi, Kazuhiro; Yoshimura, Kimio; Yamaki, Tetsuya; Kobayashi, Tomohiro*; Yoshikawa, Masahito
no journal, ,
no abstracts in English
Yoshimura, Kimio; Hakoda, Teruyuki; Yamamoto, Shunya; Yoshikawa, Masahito
no journal, ,
no abstracts in English
Yamamoto, Shunya; Hakoda, Teruyuki; Kawaguchi, Kazuhiro; Yoshimura, Kimio; Yoshikawa, Masahito
no journal, ,
no abstracts in English
substrate by ion irradiationKawaguchi, Kazuhiro; Takahiro, Katsumi*; Yoshimura, Kimio; Yamamoto, Shunya; Yoshikawa, Masahito
no journal, ,
no abstracts in English
Yoshimura, Kimio; Sugimoto, Masaki; Yoshikawa, Masahito
no journal, ,
no abstracts in English
-ray pre-irradiation grafting; Effect of the structure of quaternary ammonium ionsKoshikawa, Hiroshi; Yamaki, Tetsuya; Asano, Masaharu; Yoshimura, Kimio; Maekawa, Yasunari; Yamamoto, Kazuya*; Shishitani, Hideyuki*; Asazawa, Koichiro*; Yamaguchi, Susumu*; Tanaka, Hirohisa*
no journal, ,
We investigated the effect of the length of the linear chain on the structure of quaternary ammonium ions on the membrane properties such as durability of ion conductivity. Graft polymerization was performed by immersing the pre-irradiated ETFE film in the CMS solution. The ETFE-g-CMS film was then quaternized in four different tertiary amines, that is, trimethylamine (n = 1), dimethylethylamine (n = 2), n-butyldimethylamine (n = 4) and n-hexyldimethylamine (n = 6) solutions. The n dependence of the OH
conductivity and chemical durability, which was represented by a residual percentage of the conductivity after treatment with a Fenton solution. When n increased from 1 to 6, the OH conductivity decreased slightly, but it still stayed 20 mS/cm for n = 6. The chemical durability seemed to increase eight-fold at the same time. The chemical attack by hydroxyl radicals on the quaternary ammonium ions would be controlled by hydrophobicity and steric hindrance of the alkyl group.
-Ray Irradiation and Adsorption Properties of Zinc bis dimethyldithiocarbamateKo, B.-S.*; Yoshimura, Kimio; Sinananwanich, W.*; Maekawa, Yasunari
no journal, ,
Diallyl phthalate-contained 1-Allyl-2-thiourea (FDA/ATU) was chemically combined on the poly(styrene-co-divinylbenzene) (PSD) particle surface by ray irradiation method. The adsorption of zinc ions was found to increase with increasing the amount of ATU on the PSD particles. The adsorption of zinc ions was strongly dependent of the pH, and the maximum effect was demonstrated in the region of pH 5-7. At pH 7, the amount of zinc adsorption increased 2.64 times compared with the untreated PSD particles. The adsorbed zinc ions adsorbed on the modified PSD particles suppressed the decomposition of Zinc bis(dimethyldithiocarbamate) (Ziram), and thus increased its adsorption capacity. In addition, the FDA/ATU-modified PSD particles could be used repeatedly with a high level of the Ziram adsorption and recovery ability. Therefore, a simple and quick solid phase adsorption process of the Ziram analysis could be established using the FDA/ATU-modified PSD particles.
Sugimoto, Masaki; Yoshimura, Kimio; Idesaki, Akira; Yoshikawa, Masahito; Seki, Shu*
no journal, ,
no abstracts in English
-ray pre-irradiation grafting; Effect of the structure of quaternary ammonium ionsKoshikawa, Hiroshi; Asano, Masaharu; Yamaki, Tetsuya; Yoshimura, Kimio; Maekawa, Yasunari; Yamamoto, Kazuya*; Shishitani, Hideyuki*; Asazawa, Koichiro*; Yamaguchi, Susumu*; Tanaka, Hirohisa*
no journal, ,
We investigated the effect of a linear carbon chain length (n) in quaternary ammonium ions, on the durability of ion conductivity of anion exchange membrane. The poly(ethylene-co-tetrafluoroethylene) grafted chloromethylstyrene film was quaternized in four different tertiary amines, that is, trimethylamine (n=1), dimethylethylamine (n=2), n-butyldimethylamine (n=4) and n-hexyldimethylamine (n=6) solutions. The n dependence of ion conductivity and chemical durability, which was represented by a residual percentage of the conductivity after treatment with a Fenton solution (3% hydrogen peroxide+ 4 ppm iron sulfate) at 80 C for 2 h. When n increased from 1 to 6, the ion conductivity decreased slightly, but it still stayed 20 mS/cm for n = 6. Interestingly, the chemical durability seemed to increase eight-fold at the same time. The chemical attack by hydroxyl radicals on the quaternary ammonium ions would be controlled by hydrophobicity and steric hindrance of the alkyl group.
