1992 Fiscal Year Final Research Report Summary
Radiation damage of polymers studied by positron annihilation
| Project/Area Number |
03680199
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Nuclear engineering
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| Research Institution | NATIONAL LABORATORY FOR HIGH ENERGY PHYSICS |
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Principal Investigator |
SUZUKI Takenori NATIONAL LABORATORY FOR HIGH ENERGY PHYSICS, RADIATION SAFETY CONTROL CENTER, ASSOCIATE PROFESSOR, 放射線安全管理センター, 助教授 (40162961)
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| Co-Investigator(Kenkyū-buntansha) |
NUMAJIRI Masaharu SAME AS ABOVE, RESEARCH ASSOCIATE, 放射線安全管理センター, 助手 (20189385)
OKI Yuichi SAME AS ABOVE, RESEARCH ASSOCIATE, 放射線安全管理センター, 助手 (40204094)
MIURA Taichi SAME AS ABOVE, RESEARCH ASSOCIATE, 放射線安全管理センター, 助手 (80209717)
KONDO Kenjiro SAME AS ABOVE, PROFESSOR, 放射線安全管理センター, 教授 (20004434)
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| Project Period (FY) |
1991 – 1992
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| Keywords | POSITRON ANNIHILATION / POSITRONIUM / POLYMER / POLYMERIZATION / POLYETHYLENE / EPOXY RESINS / FREE VOLUME HOLES / INTEGRATED CIRCUITS |
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| Research Abstract |
This research program aims at the application of positron annihilation for studying characteristics of polymers : especially radiation damaged polymers.
First year of this research, 5 kinds of polyethylenes (PE) : high density PE (HDPE), linear low density PE (LLDPE), branched low density PE (BLDPE), ultra-high molecular weight PE (UHMWPE), and fully stretched PE (TEKMIRON), were employed for radiation damage experiments. TEKMIRON has 100 times larger mechanical strength than the others, but after irradiation of 3MGy its strength is reduced 1/10 of unirradiated materials, while the other's strength is reduced only 1/2. From experiments of positron annihilation (PA), intensities (I3) and lifetimes (tau3) of ortho-Ps are obtained. I3 and tau 3 of TEKMIRON are smaller than that of others.
This can be explained by the crystallinity. Correlation was obtained between PA parameters and strength of irradiated PE.
Second year, characteristics of positrons are extensively applied to study state transition from liquid to solid, thermal oxidation effect of PE, and three dimensional network structure of novolach epoxy resins. Especially, PA is effective to study the state transition and this work is the first approach to investigate polymerization of epoxy resins. Furthermore, PA has been applied to widely utilized novolach epoxy resins for integrated circuit industries and it has been shown that moisture resistence is strongly correlated with the size of holes in polymers.
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