1998 Fiscal Year Final Research Report Summary
Studies on Development of Tough Polymeric Materials at Cryogenic Temperatures
| Project/Area Number |
09650760
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | Kyoto Institute of Technology |
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Principal Investigator |
YANO Okimichi Kyoto Institute of Technology, Faculty fo Textile Science, Associate Professor, 繊維学部, 助教授 (00010942)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Polyethylene Terephthalate / Polyethylene Naphthalate / PMMA / Cryogenic Property / Mechanical Property / Dielectric Property / Physical Aging |
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| Research Abstract |
Effects of physical aging have been investigated by thermal and dielectric measurements for Poly(methyl methacrylate)(PMMA), poly(ethyl methacrylate)(PEMA), and PMMA labeled with NLO dye(p-nitroaniline and N-methyl-4-nitroaniline) in part of the side chain. The increase of the endothermic peak area and the high temperature shift of the peak position were observed as the physical aging time increased for all samples measured in this study.
We were able to observe clearly the change from closely packed state by physical aging to the equilibrium state in the temperature dependence of dielectric loss tangent. The change appeared in both the real and imaginary parts of the dielectric constant and the frequency dependence did not exist. This results indicate that new idea about the structural change due to physical aging is necessary.
2. Copolyesters of PET(polyethylene terephthalate) and PEN(polyethylene-2,6-naphthalene dicarboxylate) with composition of PET/PEN= 90/10 was prepared. Amorphous film was obtained by pressing above the melting point and quenching in ice water(sample 1). Uniaxial free width 5 times stretching film was prepared from sample 1 (sample 3). Sample 1 and sample 3 were annealed at 347K for 24hr(sample3 and sample 4, respectively). Dielectric gamma relaxation(-50K at 1 0kHz) observed for sample 3 and decreased clearly for sample 4. As this relaxation was assigned as the motion of defect region, effects of physical aging are diminution of defect region or suppression of defect's motion. For temperature dependence of the tensile modulus at 0.1 Hz, the modulus of sample 2 was high value than that of sample 1 in the temperature range from 100K to 300K.In tensile test at 77K, Young's modulus of sample 2 showed high value than that of sample 1.But, Young's modulus, tensile strength at break and ultimate elongation of sample 4 were low value than these of sample 3.
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