The science of metastable states appearing in stretched polymer
| Project/Area Number |
16K05913
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Polymer/Textile materials
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Research Collaborator |
SIRILUX Poompradub
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| Project Period (FY) |
2016-10-21 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2016: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | 伸長結晶化 / 表面エネルギー / 結晶核生成 / 形態エントロピー変化 / 天然ゴム / 高分子ネットワーク / 融点 / 表面自由エネルギー / 配向 / 高分子結晶 / ゴム |
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| Outline of Final Research Achievements |
When natural rubber with low cross-linking density is quickly stretched, it becomes a semicrystalline metastable state and memorizes its shape. This study was conducted to clarify the factors that lead to this metastable state.
The crystals formed by stretching were found to have high melting point because of their stable surface structure, and as a result, they maintain their shape without melting even after the release from the tension. We also reexamined the equilibrium melting point of natural rubber and found that it is near 60 deg.C, which is higher by nearly 25 deg.C than previously reported value. We newly found that ordinary rubber is affected by the contraction force of the elongated amorphous chains, and has melting point lower than expected by the previous theory.
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| Academic Significance and Societal Importance of the Research Achievements |
伸長した高分子の結晶化は、成形加工やゴムの自己補強効果と関係する、重要な現象である。これまで、伸長の及ぼす効果は分子の形状変化によって説明されていたが、5桁以上にも及ぶ結晶化速度の向上や、本研究で取り上げた準安定状態の出現を説明することは出来なかった。本研究では、伸長により生成する結晶の表面構造が静置下で生成する折り畳み結晶とは異なる安定なものである事を見出した。また、そのために結晶化が促進される効果は、従来考えられていた分子の形状変化よりも遙かに大きく、急激な結晶化速度の向上を説明するに十分である。これは伸長した高分子の結晶化に関する新しい概念であり、当該分野の発展に繋がると期待される。
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Report
(4 results)
Research Products
(17 results)
