Fabrication of Pt nanoparticle incorporated polymer nanowires by high energy ion and electron beam irradiation

Tsukuda, Satoshi*; Takahashi, Ryota*; Seki, Shuhei*; Sugimoto, Masaki; Idesaki, Akira; Yoshikawa, Masahito; Tanaka, Shunichiro*

Radiation Physics and Chemistry, 118, p.16 - 20, 2016/01

https://doi.org/10.1016/j.radphyschem.2015.05.029

Polyvinylpyrrolidone (PVP)-Pt nanoparticles (NPs) hybrid nanowires were fabricated by high energy ion beam irradiation to PVP thin films including HPtCl. Single ion hitting caused crosslinking reactions of PVP and reduction of Pt ions within local cylindrical area along an ion trajectory (ion track); therefore, the PVP nanowires including Pt NPs were formed and isolated on Si substrate after wet-development procedure. The number of Pt NPs was easily controlled by the mixed ratio of PVP and HPtCl. However, increasing the amount of HPtCl led to decreasing the radial size and separation of the hybrid nanowires during the wet-development. Additional electron beam irradiation after ion beam improved separation of the nanowires and controlled radial sizes due to an increase in the density of crosslinking points inner the nanowires.

Swelling of radiation-cured polymer precursor powder for silicon carbide by pyrolysis

Takeyama, Akinori; Idesaki, Akira; Sugimoto, Masaki; Yoshikawa, Masahito

Journal of Asian Ceramic Societies (Internet), 3(4), p.402 - 406, 2015/12

https://doi.org/10.1016/j.jascer.2015.08.003

Observation of oxidized region in -ray irradiated polyethylene with KOH treatment and SEM-EDS

Shimada, Akihiko; Sugimoto, Masaki; Yoshikawa, Masahito

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 30, 2015/03

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2014-050.pdf#page=62

In case of the accelerated ageing test on polymer cable insulation used for the nuclear power facility, it is very important to recognize whether oxygen penetrates in the polymer wholly or not. To confirm this, there are the method by which polymer is soaked in the KOH solution at 70C for 5 minutes, dried and observed by a SEM-EDS, only for ethylene propylene rubber, one of the polymers. This study is to apply that method for polyethylene. Polyethylene sheet of 2 mm thickness was irradiated by ray at a dose rate of 2 kGy/h for 400 h. A piece of irradiated polyethylene was picked up and the piece was soaked in the KOH solution for 24 h. After that, the piece was observed by a SEM-EDS. At the region within 70 micro meters from the surface, potassium is observed. It means that oxidation is occurred in this region. From now on, optimum soaking time will be examined.

Creation of database of radiation resistance on polymer materials and equipment

Shimada, Akihiko; Sugimoto, Masaki; Miyashita, Atsumi; Yoshikawa, Masahito

JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 29, 2014/03

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2013-059.pdf

Recovery from the accident at Tokyo Electric Power Company Fukushima Dai-ichi Nuclear Power Plant (NPP) is a matter of great urgency. In order to realize safe and secure operation for decontamination and decommissioning of NPP, it is indispensable to use equipments with sufficient radiation resistance (RR). In JAEA as well as other agency, various studies on RR of various materials and equipments have been conducted and a number of reports and papers have been published. Then, we started construction of a database named as "Database of Radiation Resistance on Polymer Materials and Equipments" and announced this database in a press release on June 1, 2012. At present, the database includes 878 data of materials, which are consisted of 423 data of polymer materials, 223 data of equipments and parts, 103 data of oils, fats and paintcoatings and 129 data of organic composite materials. The database will be extended and expected to be utilized for safe and secure operation.

Degradation mechanisms of Silicone Rubber (SiR) by accelerated ageing for cables of nuclear power plant

Shimada, Akihiko; Sugimoto, Masaki; Kudo, Hisaaki*; Tamura, Kiyotoshi*; Seguchi, Tadao*

IEEE Transactions on Dielectrics and Electrical Insulation, 21(1), p.16 - 23, 2014/02

https://doi.org/10.1109/TDEI.2014.6740721

The thermal and radiation ageing behaviors and degradation mechanisms of SiR for the cable insulation of nuclear power plants were studied. The thermal ageing and radiation ageing in air were conducted up to 235C and 195C, respectively. The dose rate of radiation ageing is 1 kGy/h. Thermal ageing in vacuum as well as in air was also conducted. The degraded SiR is evaluated by tensile test, gel fraction measurement, swelling ratio measurement and weight measurement, and then the results are analyzed. It is appeared that the radiation degradation of SiR at high temperature is much more severe than that of SiR at low temperature at the same dose. Focusing on the molecular structure, it is supposed that crosslinking reagents which are included in SiR are removed, oxygen atom is attached instead of the reagents and new crosslinking is foamed. Their behaviors are different from the polymer of hydrocarbon.

Degradation distribution in insulation materials of cables by accelerated thermal and radiation ageing

Shimada, Akihiko; Sugimoto, Masaki; Kudo, Hisaaki*; Tamura, Kiyotoshi*; Seguchi, Tadao*

IEEE Transactions on Dielectrics and Electrical Insulation, 20(6), p.2107 - 2116, 2013/12

https://doi.org/10.1109/TDEI.2013.6678859

The degradation of cables by the accelerated thermal and radiation ageing for nuclear power plant was studied. The thermal oxidation of crosslinked polyethylene (XLPE) as a cable insulation showed the heterogeneous features along the depth of sheet specimens. The degree of oxidation was closely related to the distribution of antioxidant content due to the decay of antioxidant content by the evaporation and radiation decomposition during accelerated ageing. The specific relations were observed between the tensile properties and the yield of oxidation products and also between the oxidation products and antioxidant content in XLPE specimens. The yields and the content and their distribution were detected by FTIR. The oxidation of XLPE containing antioxidant of enough content proceeded proportionally with ageing time or radiation dose at any ageing conditions. When the antioxidant content decreased less than a limited content by thermal and/or radiation ageing, the oxidation rate by thermal ageing increased sharply with ageing time. Therefore, the oxidation at surface of XLPE was much accelerated when the antioxidant decreased to result the heterogeneous oxidation. The mechanical properties depend closely on the degree of oxidation at the surface. The behavior of oxidation was also affected by the types of antioxidant.

Product analysis for polyethylene degradation by radiation and thermal ageing

Sugimoto, Masaki; Shimada, Akihiko; Kudo, Hisaaki*; Tamura, Kiyotoshi; Seguchi, Tadao*

Radiation Physics and Chemistry, 82, p.69 - 73, 2013/01

https://doi.org/10.1016/j.radphyschem.2012.08.009

The oxidation products formed by thermal and radiation ageing of crosslinked polyethylene for cable insulation were analyzed by FTIR-ATR spectrometry. The most of products were composed of carboxylic acid, carboxylic ester, and carboxylic anhydride. The carboxylic acid was the primal product, and the others were the secondary products by the thermal reaction of carboxylic acids. The carboxylic acid as the primal oxidation product supports the proposed new oxidation mechanisms that the main chain scission should occur directly by oxidation of polyethylene radicals.

Mechanism of antioxidant interaction on polymer oxidation by thermal and radiation ageing

Seguchi, Tadao*; Tamura, Kiyotoshi; Shimada, Akihiko; Sugimoto, Masaki; Kudo, Hisaaki*

Radiation Physics and Chemistry, 81(11), p.1747 - 1751, 2012/11

https://doi.org/10.1016/j.radphyschem.2012.06.011

The mechanism of polymer oxidation by radiation and thermal ageing was investigated for the life evaluation of cables installed in radiation environments. The antioxidant as a stabilizer was much effective for thermal oxidation with a small content in polymers, but was not effective for radiation oxidation. The ionizing radiation induced the oxidation to result chain scission even at low temperature, because the free radicals were produced and the antioxidant could not stop the oxidation of radicals with the chain scission. A new mechanism of antioxidant effect for polymer oxidation was proposed. The effect of antioxidant was not the termination of free radicals in polymer chains such as peroxy radicals, but was the depression of initial radical formation in polymer chains by thermal activation. The antioxidant molecule was assumed to delocalize the activated energy in polymer chains by Boltzmann statics (distribution) to result decrease the probability of radical formation at a given temperature. The interaction distance (delocalization area) by one antioxidant molecule was estimated to be 5-10 nm in polymer matrix, though the value would depend on the chemical structure of antioxidant.

Visualization of focused proton beam dose distribution by atomic force microscopy using blended polymer films based on polyacrylic acid

Omichi, Masaaki*; Takano, Katsuyoshi*; Sato, Takahiro; Kamiya, Tomihiro; Ishii, Yasuyuki; Okubo, Takeru; Koka, Masashi; Kada, Wataru; Sugimoto, Masaki; Nishikawa, Hiroyuki*; et al.

Journal of Nanoscience and Nanotechnology, 12, p.7401 - 7404, 2012/09

https://doi.org/10.1166/jnn.2012.6457

Fullerene nanowires as a versatile platform for organic electronics

Maeyoshi, Yuta*; Saeki, Akinori*; Suwa, Shotaro*; Omichi, Masaaki*; Marui, Hiromi*; Asano, Atsushi*; Tsukuda, Satoshi*; Sugimoto, Masaki; Kishimura, Akihiro*; Kataoka, Kazunori*; et al.

Scientific Reports (Internet), 2, p.600_1 - 600_6, 2012/08

https://doi.org/10.1038/srep00600

The development of organic semiconducting nanowires that act as charge carrier transport pathways in flexible and lightweight nano-electronics is a major scientific challenge. We report on the fabrication of fullerene nanowires that is universally applicable to its derivatives (pristine C, methanofullerenes of C and C, and indene C bis-adduct). Nanowires with radii of 811 nm were formed via a chain polymerization reaction induced by a high-energy ion beam. Fabrication of a poly(3-hexylthiophene): [6,6]-phenyl C butyric acid methyl ester (PCBM) bulk heterojunction organic photovoltaic cell including PCBM nanowires with precisely-controlled length and density demonstrates how application of this methodology can improve the power conversion efficiency of these inverted cells.