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Sakoda, Akihiro; Kono, Takahiko; Kataoka, Noriaki*; Andresz, S.*
Hoken Butsuri (Internet), 54(3), p.181 - 187, 2019/10
no abstracts in English
Nakagawa, Seiko*; Taguchi, Mitsumasa; Kimura, Atsushi; Nagasawa, Naotsugu; Hiroki, Akihiro
Nuclear Instruments and Methods in Physics Research B, 334, p.64 - 68, 2014/09
Times Cited Count:2 Percentile:19.31(Instruments & Instrumentation)N-saturated 2-propanol solutions containing styrene and maleimide were gelled by the addition of hydroxypropylcellulose and irradiated by proton, He and C-ion beams. The trend in the dose rate and LET effects on the yield and molecular weight distribution of the polymer produced in the gel was almost the same in the solution. On the contrary, the dose rate effect in the gel was higher than that in the solution. This effect was accelerated for irradiations by proton as well as heavier ion with a higher LET value.
Nakagawa, Seiko*; Taguchi, Mitsumasa; Kimura, Atsushi
Radiation Physics and Chemistry, 91, p.143 - 147, 2013/10
Times Cited Count:3 Percentile:25.83(Chemistry, Physical)The radiation-induced polymerization of styrene with maleimide was studied in methanol, ethanol, and 2-propanol solutions by irradiation of electrons and C-ions. Co-polymer of styrene and maleimide was produced in each alcohol by radiation polymerization which induced the solvent radicals. The yields of the co-polymer for irradiation of the electrons and C-ions were 2.45 and 1.85 mg/mL/kGyin methanol, 4.41 and 3.16 mg/mL/kGy in ethanol, and 4.77 and 3.67 mg/mL/kGy in 2-propanol, respectively. Because the reactivity of the solvent radical with monomers (styrene and maleimide) was considered to increase in order of methanol, ethanol, and 2-propanol. The yield of the co-polymer for irradiation of C-ions (High-LET radiation, 600 eV/nm) was lower than that of electrons (Low-LET radiation, 0.2 eV/nm).
Nakagawa, Seiko*; Taguchi, Mitsumasa; Kimura, Atsushi
Radiation Physics and Chemistry, 80(11), p.1199 - 1202, 2011/11
Times Cited Count:6 Percentile:44.45(Chemistry, Physical)N-saturated 2-propanol solutions containing styrene and maleimide were irradiated by electron, proton, He and C-ion beams. The styrene-maleimide copolymer was produced by radical polymerization induced during irradiation. The effects of the radical distribution, which depends on the LET or dose rate, on the molecular weight and the polymer yield were discussed. Both the molecular weight and the polymer yield increased by the decreasing dose rate. These effects increased by irradiation using heavier ions. The polymer yield decreased with the increasing LET value. On the other hand, irradiation at a higher LET value and lower dose rate will produce a polymer with a higher molecular weight. The distribution of radicals in time and space will have an influence on both the molecular weight and the polymer yield.
Nakagawa, Seiko*; Taguchi, Mitsumasa; Hirota, Koichi; Murakami, Takeshi*
Radiation Physics and Chemistry, 79(8), p.890 - 893, 2010/08
Times Cited Count:3 Percentile:24.16(Chemistry, Physical)Hydroxymaleimide was irradiated in N-saturated 2-propanol solutions by high-energy heavy ions over a wide range of LET values. The differential G-values of the degradation of hydroxymaleimide by irradiation with the heavier ions were lower than those of the lighter ions for the same LET value. It was opposite result obtained in the air-saturated system. The degradation efficiency was 1.5 times higher, when the dose rate was 1/10 times lower. When irradiated at an LET value lower than 8 eV/nm, the G-values converged to a value less than that obtained by -irradiation.
Nakagawa, Seiko*; Ota, Nobuaki*; Taguchi, Mitsumasa; Kojima, Takuji
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 142, 2007/02
no abstracts in English
Nakagawa, Seiko*; Ota, Nobuaki*; Taguchi, Mitsumasa; Kojima, Takuji
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no abstracts in English
Nakagawa, Seiko*; Taguchi, Mitsumasa; Kojima, Takuji
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Nakagawa, Seiko*; Ota, Nobuaki*; Taguchi, Mitsumasa
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no abstracts in English
Nakagawa, Seiko*; Taguchi, Mitsumasa; Ota, Nobuaki*; Hirota, Koichi
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Nakagawa, Seiko*; Ota, Nobuaki*; Hirota, Koichi; Taguchi, Mitsumasa
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no abstracts in English
Nakagawa, Seiko*; Taguchi, Mitsumasa; Ota, Nobuaki*; Hirota, Koichi
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Nakagawa, Seiko*; Ota, Nobuaki*; Taguchi, Mitsumasa; Hirota, Koichi
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no abstracts in English
Enomoto, Ichiro*; Soeda, Shin*; Ikeda, Shigetoshi*; Kudo, Hisaaki*; Katsumura, Yosuke
no journal, ,
Ultra High Molecular Weight Polyethylene (UHMWPE) is applied as industrial material in many fields because it has properties of lightness in weight and of high endurance. Its surface needs to be reformed to overcome its deficit of low adhesion property toward other materials. It is known that radiation graft polymerization is effective to reform surfaces of hydrophobic polymeric materials although material properties may decrease due to scissions and oxidations induced by radiolytic radicals. It is believed that such effects of irradiations appear in amorphous regions and does not in crystalline regions. However, it is recently reported by using DSC measurement or XRD analysis that irradiations can affect not only amorphous but also crystalline region. This work investigates change of microscopic structures of UHMWPE in surface region of 100 m, which is responsible for radiation graft polymerization. Analyses were conducted by combination of several techniques such as FT-IR, DSC, XRD and ESR.
Enomoto, Ichiro*; Soeda, Shin*; Katsumura, Yosuke; Kudo, Hisaaki*
no journal, ,
Ultra high molecular weight polyethylene (UHMWPE) has been widely used for industrial and biomaterials due to its chemical inertness, impact resistance and abrasion resistance. However, because of no reactive group on a polyethylene backbone or low surface energy, the surface is hydrophobic, not adhesive and has a low dyeing affinity. Therefore, surface treatment has been applied to modify the property. Especially, the radiation induced graft polymerization method is excellent to maintain the modification for a prolonged period. We investigated efficiency of graft polymerization of acrylic acid (AA), methyl methacrylate (MMA) and styrene (St) to the UHMWPE fiber irradiated in surface modification. Mechanisms of reactions in the radiation graft polymerization were also investigated.
Enomoto, Ichiro*; Katsumura, Yosuke; Kudo, Hisaaki*; Soeda, Shin*
no journal, ,
Ultra high molecular weight polyethylene (UHMWPE) has been widely used for industrial and biomaterials due to its chemical inertness, impact resistance and abrasion resistance. However, because of no reactive group on a polyethylene backbone or low surface energy, the surface is hydrophobic, not adhesive and has a low dyeing affinity. Therefore, surface treatment has been applied to modify the property. Especially, the radiation induced graft polymerization method is excellent to maintain the modification for a prolonged period. We investigated efficiency of graft polymerization of acrylic acid (AA), methyl methacrylate (MMA) and styrene (St) to the UHMWPE fiber irradiated in surface modification. Mechanisms of reactions in the radiation graft polymerization were also investigated. Especially, role of hydroperoxide as a precursor of radiation-induced polymerization was investigated.
Enomoto, Ichiro*; Katsumura, Yosuke; Soeda, Shin*; Fujishiro, Satoshi*
no journal, ,
no abstracts in English
Nakagawa, Seiko*; Taguchi, Mitsumasa; Kimura, Atsushi
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no abstracts in English