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Takahashi, Shuichi; Maekawa, Yasunari; Hagiwara, Tokio*; Okonogi, Hiroyuki*
no journal, ,
Methyl acrylate monomer was grafted by 
-ray irradiation on a poly(ethylene-co-tetrafluoroethylene)(ETFE) film. Then, the novel polymer electrolyte membranes (PEM), which possess alkyl sulfonic acids on grafted chain, were synthesized by polymeric transformation of functional groups. The PEM prepared by the above approach were analyzed structurally and characterized well.
-irradiationAsano, Masaharu; Yamaki, Tetsuya; Maekawa, Yasunari; Yoshida, Masaru; Kanega, Jun*; Enokida, Takashi*
no journal, ,
no abstracts in English
Sato, Ken; Narita, Tadashi*; Takahashi, Shuichi; Hasegawa, Shin; Maekawa, Yasunari
no journal, ,
Radiation-grafting technique has been applied for the preparation of polymer electrolyte membranes of super engineering plastics, PES and PEEK. The radiation grafting of styrene on to a PEEK film proceeded to give grafted films (PEEK-g-Sty). The milder sulfonation condition of PEEK-g-Sty lead sulfonated PEEK-g-Sty with controlled sulfonation degrees and promising ion exchange capacity(IEC). By controlling graft and sulfonation degrees, PEEK films were transformed into the polymer electrolyte membranes exhibiting proton conductivity of 0.001 - 0.01 S/cm.
Chen, J.; Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru
no journal, ,
Novel one step preparation of polymer electrolyte membranes without a membrane casting process is achieved by radiation crosslinking of a polyetheretherketone (PEEK) film to prevent dissolution and deformation of the original film in sulfonating solutions. The films crosslinked with doses more than 14 MGy can be effectively sulfonated at 0 degree in a 0.2 M solution of ClSO3H in dichloroethane, resulting in a crosslinked and sulfonated PEEK (sPEEK) electrolyte membrane with high proton conductivity (0.038 - 0.069 S/cm) comparable to Nafion. Nevertheless, its lowest water uptake is slightly high for application in polymer electrolyte membrane fuel cell (PEMFC). The heat-treatment was effective for further crosslinking of the membrane; as a result, the water uptake drastically decreased, compensating for a slight decrease of proton conductivity (from 0.069 to 0.057 S/cm). In addition, the double crosslinked sPEEK electrolyte membrane exhibited mechanical and thermal properties superior to those of Nafion.
Motokawa, Ryuhei; Koizumi, Satoshi; Hashimoto, Takeji; Iida, You*; Kawakatsu, Toshihiro
no journal, ,
We constructed a focusing ultra-small-angle scattering spectrometer (SANS-J-II) at research reactor JRR-3, Tokai, Japan. Focusing ultra-small-angle neutron scattering (USANS) and conventional small-angle neutron scattering (SANS) can observe the length scale about 1000 nm - 100 nm and 100 nm - 1 nm, respectively. Focusing USANS, thus realized, plays an important role to investigate the time-evolution of hierarchically ordered structures in the living radical polymerization solution, preparing poly(methyl methacrylate)-block-polystyrene. In the reaction process to synthesize PS block chains from the end of PMMA block chain, we found the interplay between macro and microdomain structures as follows. As the polymerization proceeds, (1) first by polymerization-induced disorder-order transition, a lamellar microdomain appears and (2) second by order-order transitions, the morphologies of microdomains change to PMMA cylinder and successively to PMMA sphere.
Noda, Yohei; Koizumi, Satoshi; Hashimoto, Takeji; Shimono, Satoshi*; Baba, Masaaki*; Yamauchi, Jun*; Ikuma, Naohiko*; Uchida, Yoshiaki*; Tamura, Rui*; Iima, Yoshio*
no journal, ,
Recently, the chiral paramagnetic liquid crystals (LCs) were synthesized, whose spin sources are fixed in their rigid core. Their responses to an electric and magnetic fields are attractive topics. In general, LC molecules align with the rubbing direction on the oriented film of the LC cell. By far, by use of this surface stabilization effect on LC cell surface, we have developed this potential method of the EPR measurement with rotating the oriented LC cell sample. More recently, the chiral paramagnetic LC showing ferroelectricity was synthesized. We will report the EPR investigation of the orientation change of the ferroelectric LC in response to the switching of an applied electric field. It was shown by the EPR measurement that with no electric field, the LC molecules directed nearly uniformly along the rubbing direction on the cell surface, on the other hand, with electric field (24V), the LC molecules largely tilted from the normal line of the smectic layer.
Zhao, Y.; Miyamoto, Nobuyoshi; Koizumi, Satoshi; Hashimoto, Takeji
no journal, ,
The simultaneous living anionic copolymerization of isoprene (I) and styrene-d8 (S) monomers, initiated by sec-butyllithium in benzene-d6, was investigated by means of time-resolved SANS, UV-Vis spectroscopy, SEC, and NMR. The results revealed the 3 time regions. In region 1, random copolymers rich in isoprene (80 wt%) were synthesized. SANS intensity was weak and almost time-independent, and UV-vis absorbance at 450 nm was very weak. In region 2, styrene-d8-rich random block sequences were formed to result in the block copolymers. A broad scattering peak appeared in SANS, aggregation number changed from 4 to 2 at the end of this region. In region 3, the remaining S underwent a rapid polymerization into polystyrene (PS), leading to the formation of P(I-ran-S)-block-P(S-ran-I)-block-PS. Polymerization-induced disorder-to-order transition and order-to-order transition from hex-cylinder to lamella occurred.
Koizumi, Satoshi
no journal, ,
no abstracts in English
Masui, Tomomi; Shikinaka, Kazuhiro*; Kwon, H.*; Koizumi, Satoshi; Hashimoto, Takeji; Iwase, Hiroki; Kakugo, Akira*; Gong, J.*
no journal, ,
no abstracts in English
Iwase, Hiroki; Koizumi, Satoshi; Hashimoto, Takeji; Yamaki, Tetsuya; Sawada, Shinichi; Maekawa, Yasunari
no journal, ,
By using ultra-small-angle neutron scattering (USANS) techniques, we have investigated the hierarchical structures of the crosslinked-polytetrafluoroethylene (PTFE) electrolyte membrane, which is made by using both radiation-crosslinking and radiation-induced grafting of styrene, in order to reveal the correlation between the hierarchical structure and a proton conducting mechanism. We observed structural changes of crosslinking PTFE electrolyte membrane in each synthetic process and compared the structures between the crosslinking PTFE electrolyte membrane and Nafion112 under swollen state. We detected each efects of radiation crosslinking and grafting, respectively on the scattering profiles. Scattering profile for swollen crosslinking PTFE electrolyte membrane in D
O has a no peak around 
=0.12 
. where scattering profile for Nafion has a peak reflected the ion-cluster structure. However, a shoulder-like profile is appeared clearly at 
. This peak-position is agreement with that observed in the scattering profile after radiation-crosslinking process. The presented results suggested that the structure formed by the radiation-crosslinking is close relation with the proton conductivity for the crosslinking PTFE electrolyte membrane.
Yamaguchi, Daisuke; Mayama, Hiroyuki*; Koizumi, Satoshi; Tsujii, Kaoru*; Hashimoto, Takeji
no journal, ,
The fractal dimensions of specific porous silica materials were investigated by ultra-small-angle neutron scattering (USANS). In order to control the fractal dimension of porous silica material, flaky particles made of alkylletene dimer (AKD) were employed as moulds and silica matrix was formed by sol-gel process. The fractal dimension of the pores was changeable by the compression of the AKD mould at different ratio (hereafter designated as r) before the mould was filled with a TMOS solution, which turned to silica matrix, and three specimens, of which r = 1, 2, and 3, were prepared. USANS measurements brought us wide-q observations of the specimens, in the q scale of more than three orders of magnitude, and made it possible to accurate evaluation of the fractal dimension. The resultant mass-fractal dimensions for the specimens of r = 1, 2, and 3 were 2.98, 2.74, and 2.67, respectively.