1993 Fiscal Year Final Research Report Summary
A Study on Higher-Order Structure and Molecular Motions of the ionic cluster in ionomer
| Project/Area Number |
04650808
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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 |
高分子物性・高分子材料（含機械材料）
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| Research Institution | Nagoya Institute of Technology |
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Principal Investigator |
TSUJITA Yoshiharu Nagoya Institute of Technology, Dep.Mat.Scl.and Eng., Prof., 工学部, 教授 (70016591)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIMIZU Hiroaki Nagoya Institute of Technology, Dep.Mat.Scl.and Eng., Assistant Prof., 工学部, 助手 (10240350)
KINOSHITA Takatoshi Nagoya Institute of Technology, Dep.Mat.Scl.and Eng., Associate Prof., 工学部, 助教授 (60135407)
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| Project Period (FY) |
1992 – 1993
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| Keywords | ionomers / ionic Cluster / Ethylene Matrix / the Crystallites Formed by Annealing / DSC / Viscoelastioity / Solid-State NMR / Spin-Probe ESR Method |
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| Research Abstract |
Two endothermic peaks observed by DSC measurement around 50 - 60 ﾟC and 90 ﾟC for as received poly(ethylene-co-methacrylic acid) and its salts were attributed to the melting of polyethylene crystallites. After annealing in the cooling process, the lower temperature peak was observed at a temperature slightly higher than the annealing temperature. The lower temperature peak corresponded to the melting of the crystallites formed by the annealing and the higher one to that by cooling. The crystallization of ionomer is hindered by the presence of ionic aggregates which play a role of crosslinking. Consequently the crystallization of ionomer aged, that is, annealed at room temperature is much more remarkable than that of the copolymer or low density polyethylene. The ^<13>C spin-lattice relaxation time of the crystalline region of ionomer was shorter than that of polyethylene. This finding is suggested that size of crystal in the ionomers were relatively small than that in polyethylene. Similar interpretations on the crystal size of the ionomers were obtained from the discussion about ^1H spin-diffusion with ^1H spin-lattice relaxation times in the laboratory and rotating frames. On the other hand, the mobility of methacrylic molety in the ionic cluster was restricted in comparison with that in ethylene-methacrylic acid copolymer. Next, to discuss the motion of amorphous region, spin-probe ESR method was carried out. The temperature at which the separation of the outmost peaks of the ESR spectrum of spin-probe in polymer matrix is 50G (T_<50G>), is a valuable tool for Tg determination. The values of T_<50G> for TEMPO-containing ionomers were estimated to be about -20 ﾟC - 20 ﾟC and -25 ﾟC at low and high neutralization, respectively. This finding show that there is the distribution of the dynamical features of amorphous region in the ionomer, and the distribution changes with the neutralization.
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