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Nagasawa, Naotsugu; Yagi, Toshiaki; Tamada, Masao; Pham, T. L. H.*
no journal, ,
Recently, we have reported the synthesis of hydrogels of polysaccharide derivatives such as carboxymethylcellulose (CMC), carboxymethylchitin, etc., by radiation-induced crosslinking methods. Control of gelation of polysaccharide derivatives by radiation is very important factor for various applications. It was investigated that control temperature during irradiation affects on crosslinking behavior of CMC. The gel fraction and swelling of CMC gel after irradiation at temperature of -78 to 70 
C were determined. The more pronounced gelation was occurred in lower temperature region of -78 to 0 C when compared to the other region of 0 to 70 C. It found that gelation could be controlled by changing temperature at the time of the irradiation when it was made to put a polysaccharide derivative such as CMCT and CMS on the crosslinking with the radiation and gel was formed.
Hiroki, Akihiro; Yamaki, Tetsuya; Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru
no journal, ,
no abstracts in English
Yamaguchi, Daisuke; Miyamoto, Nobuyoshi; Koizumi, Satoshi; Nakato, Teruyuki*; Hashimoto, Takeji
no journal, ,
The exfoliated K
Nb
O
nanosheets in the aqueous solutions were observed by (ultra-) small-angle neutron and X-ray scattering (SANS, USANS and USAXS). A comprehensive measurement revealed the assembled structure of nanosheets in wide range of q, from 3
10
nm
to 1 nm, where q is the magnitude of scattering vector. The details of liquid crystalline structure formed by [NbO]
nanosheets, which was reflected on the scattering at higher q region (
310
(nm)), largely depend on the nanosheet lateral dimension or its volume fraction. On the other hand, at lower q region (
110 (nm)), the scattering profile shows a power law scattering of which index is -2.5 regardless of the nanosheet lateral dimension or its volume fraction, suggesting that at large scale nanosheets take similar mass fractal distribution.
Miyamoto, Nobuyoshi; Tanaka, Hirokazu*; Yamauchi, Kazuhiro*; Hasegawa, Hirokazu*; Hashimoto, Takeji; Koizumi, Satoshi
no journal, ,
The living anionic polymerization processes of polyisoprene, polystyrene, and polystyrene-block-polyisoprene were studied by in-situ small-angle neutron scattering (SANS) in combination with gel permeation chromatography and uv-visible spectroscopy. The polymerization reactions were carried out in benzene-d6 with sec-butyllithium as the initiator. The SANS intensity largely decreased upon termination of the living ends, indicating the presence of ionic aggregates during polymerization. The time-courses of the aggregation number f in the aggregates during the polymerizations were quantitatively estimated by analyzing the time-resolved SANS data on the basis of the model of star-polymer. In isoprene systems, the aggregation number decreased from ca. 10 to 4 with increasing molecular weight.
Motokawa, Ryuhei; Zhao, Y.*; Hashimoto, Takeji; Koizumi, Satoshi
no journal, ,
no abstracts in English
Hashimoto, Takeji; Motokawa, Ryuhei; Terashima, Takaya*; Sawamoto, Mitsuo*; Kamigaito, Masami*; Koizumi, Satoshi
no journal, ,
no abstracts in English
Koizumi, Satoshi; Motokawa, Ryuhei; Iwase, Hiroki; Hashimoto, Takeji
no journal, ,
no abstracts in English
Iwase, Hiroki; Koizumi, Satoshi; Yoshimura, Tomokazu*; Hashimoto, Takeji
no journal, ,
no abstracts in English
Wada, Yuki; Tamada, Masao; Seko, Noriaki; Mitomo, Hiroshi*
no journal, ,
no abstracts in English