| Project/Area Number |
18K14282
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 35020:Polymer materials-related
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| Research Institution | Japan Advanced Institute of Science and Technology |
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Principal Investigator |
Enta Panitha 北陸先端科学技術大学院大学, 先端科学技術研究科, 助教 (10808653)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | polypropylene / nucleation / morphology / molecular orientation / Cavitation / Polypropylene / Nucleating agent / Molecular weight / Morphology / Mechanical anisotropy / Molecular orientation / nucleating agent / drawdown force / alpha-form crystal / crystallization / Molecular control / polymer processing |
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| Outline of Final Research Achievements |
In extrusion process, polypropylene (PP) films containing the specific β nucleating agent exhibit the anomalous molecular orientation, in which PP chains are oriented perpendicular to the flow direction, irrespective of the molecular weights of PP. We explained that the deformation behavior of the extruded sheet depends on the stretching direction. As the microvoid formation occurs during stretching in a machine direction, a sufficient amount of tie molecules connecting between crystallites is required for highly porous structure. Moreover, the transformation of crystalline phase as well as the rotation of chain axis during stretching is responsible for the frequent void opening. These results indicate that the anisotropy of both the crystalline phase and the amorphous regions is responsible for the different morphologies during the deformation. The material would be applicable to the development of microporous films for battery separators.
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| Academic Significance and Societal Importance of the Research Achievements |
The fact that plastic deformation mechanism is strongly dependent on the deformation direction leads to further understanding of deformation behavior of not only PP but also any crystalline polymers. The finding will widen the material design in both extrusion and injection-molding processes.
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