Refine your search:     
Report No.
 - 
Search Results: Records 1-18 displayed on this page of 18
  • 1

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Establishment and activities of Young Generation Network (IRPA YGN) in International Radiation Protection Association

Sakoda, Akihiro; Kono, Takahiko; Kataoka, Noriaki*; Andresz, S.*

Hoken Butsuri (Internet), 54(3), p.181 - 187, 2019/10

no abstracts in English

Journal Articles

LET and dose rate effect on radiation-induced copolymerization in physical gel

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$$_{2}$$-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.

Journal Articles

Solvent effect on copolymerization of maleimide with styrene induced by irradiation of ion and electron beams

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).

Journal Articles

LET and dose rate effect on radiation-induced copolymerization of maleimide with styrene in 2-propanol solution

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$$_{2}$$-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.

Journal Articles

Degradation of hydroxymaleimide in 2-propanol by irradiation of energetic heavy ions, 2; N$$_{2}$$-saturated system

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$$_{2}$$-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 $$gamma$$-irradiation.

Journal Articles

LET effect on irradiation of hydroxy imide compounds in alcohol solution

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

Oral presentation

LET effect on irradiation of hydroxy imide compounds in alcohol solutions

Nakagawa, Seiko*; Ota, Nobuaki*; Taguchi, Mitsumasa; Kojima, Takuji

no journal, , 

no abstracts in English

Oral presentation

LET effect on radiation of hydroxymaleimide in 2-propanol

Nakagawa, Seiko*; Taguchi, Mitsumasa; Kojima, Takuji

no journal, , 

no abstracts in English

Oral presentation

LET effect of hydroxy imide compounds in alcohol solution

Nakagawa, Seiko*; Ota, Nobuaki*; Taguchi, Mitsumasa

no journal, , 

no abstracts in English

Oral presentation

Degradation of hydroxymaleimide in 2-propanol by irradiation of $$gamma$$-ray and energetic heavy ions

Nakagawa, Seiko*; Taguchi, Mitsumasa; Ota, Nobuaki*; Hirota, Koichi

no journal, , 

no abstracts in English

Oral presentation

LET effect on radiation of hydroxymaleimide in 2-propanol, 2

Nakagawa, Seiko*; Ota, Nobuaki*; Hirota, Koichi; Taguchi, Mitsumasa

no journal, , 

no abstracts in English

Oral presentation

Degradation of hydroxymaleimide in N$$_{2}$$-saturated 2-propanol by irradiation of energetic ions

Nakagawa, Seiko*; Taguchi, Mitsumasa; Ota, Nobuaki*; Hirota, Koichi

no journal, , 

no abstracts in English

Oral presentation

LET effect on irradiation of hydroxymaleimide in N2-saturated 2-propanol

Nakagawa, Seiko*; Ota, Nobuaki*; Taguchi, Mitsumasa; Hirota, Koichi

no journal, , 

no abstracts in English

Oral presentation

Change of the micro structure of ultra high molecular weight polyethylene by irradiation

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 $$sim$$100 $$mu$$m, which is responsible for radiation graft polymerization. Analyses were conducted by combination of several techniques such as FT-IR, DSC, XRD and ESR.

Oral presentation

Surface modification of ultra high molecular weight polyethylene by radiation induced graft polymerization

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.

Oral presentation

The Role of hydroperoxide as a precursor of radiation induced graft polymerization

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.

Oral presentation

Dyeing properties of radiation grafted ultra high molecular weight polyethylene

Enomoto, Ichiro*; Katsumura, Yosuke; Soeda, Shin*; Fujishiro, Satoshi*

no journal, , 

no abstracts in English

Oral presentation

Dose rate and LET effect on radiation induced polymerization

Nakagawa, Seiko*; Taguchi, Mitsumasa; Kimura, Atsushi

no journal, , 

no abstracts in English

18 (Records 1-18 displayed on this page)
  • 1