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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：15 Percentile：45.37(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.
Enomoto, Kazuyuki; Takahashi, Shuichi; Maekawa, Yasunari
Macromolecular Chemistry and Physics, 213(1), p.72 - 78, 2012/01
Times Cited Count：10 Percentile：32.97(Polymer Science)Most polymer grafts in grafted polymer films obtained by radiation-induced solid graft polymerization have not been analyzed in detail due to difficulties in isolation of the grafts without structural decomposition. We report herein a novel structural and molecular weight characterization method for polymer grafts chemically attached to thermally and chemically stable polymer substrates, based on swelling-induced graft detachment in hot water. The polymer grafts prepared by radiation-induced polymerization of alkyl acrylate into poly(ethylene-co-tetrafluoroethylene) (ETFE) followed by a sulfonation reaction were found to have a ternary copolymer structure whose monomer units contained -COOH, -SO
H, or both.
Maekawa, Yasunari; Kato, Jun*; Katakai, Masashi*; Ishihara, Masaaki*; Enomoto, Kazuyuki; Hagiwara, Tokio*; Ishii, Tatsuhito*; Ito, Kazuo*; Koshikawa, Hiroshi; Yoshida, Masaru
Macromolecular Chemistry and Physics, 209(6), p.625 - 633, 2008/03
Times Cited Count：2 Percentile：7.31(Polymer Science)A polysulfonamide and copolymers consisting of sulfonamides and amides underwent Fries rearrangement and scission, forming amino groups upon EB irradiation. The EB irradiation of these films with a dose of 500 
C/cm
followed by the color forming reaction provided the color imaging of line/space patterns with resolution of 300 nm.
Li, J.; Maekawa, Yasunari; Yamaki, Tetsuya; Yoshida, Masaru
Macromolecular Chemistry and Physics, 203(17), p.2470 - 2474, 2002/12
Times Cited Count：13 Percentile：42.63(Polymer Science)Chemical modification of the hydrophilic surface of poly(ethylene terephthalate) (PET) was examined by the selective alkylation of the acid salt on the surface using acylbromides as an electrophile with catalytic potassium fluoride. The hydrophobicity of the PET surface increased as the alkylation reaction of the hydrolyzed surface proceeded. The chemical incorporation of the alkylation reagents was confirmed by the fluorine peaks in X-ray photoelectron spectroscopy (XPS) from the fluorinated reagents. Exponential increases were observed in the emission and excitation intensities of fluorescence spectra during the reaction of the surface with a fluorescent reagent. This indicated the esterification of carboxylic acids on the surface without deterioration of the reactions even at the later stages. The relation between changes in contact angles and the fluorescence spectra revealed that the hydrophobicity of a surface was quickly restored at the beginning of a reaction.
