2002 Fiscal Year Final Research Report Summary
Molecular Dynamics of Polymer Crystallization-Toward a First-Principle Molecular Design of Polymers-
| Project/Area Number |
12127206
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Yamaguchi University |
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Principal Investigator |
YAMAMOTO Takashi Yamaguchi University, Department of Physics, Biology, and Informatics, Professor, 理学部, 教授 (00127797)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Susumu Kyoto Institute of Technology, Department of Polymer Science and Engineering, Associate Professor, 繊維学部, 助教授 (30280598)
URAKAMI Naohito Yamaguchi University, Department of Physics, Biology, and Informatics, Assistant Professor, 理学部, 助手 (50314795)
NAZAKI Koji Yamaguchi University, Department of Physics, Biology, and Informatics, Associate Professor, 理学部, 助教授 (80253136)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Polymer crystallization / Molecular simulation / Primary nucleation / Crystal growth / Chain folding / Surface ordering / Molecular dynamics simulation |
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| Research Abstract |
(1)Molecular dynamics simulation of polymer crystallization from the melt Molecular pathways to polymer crystallization and the structures of crystal-melt interfaces are investigated by molecular dynamics simulation. We clearly observe the growth of stacked chain-folded lamellae from the substrates. The growing lamellae have a definite tapered shape, and they show marked thickening growth along the chain axis as well as usual growth perpendicular to it. The overall crystallization rate is found to be very sensitive to the crystallization temperature, showing an apparent maximum around 320K-330K for C_100-We find that the lamellae do not grow keeping pace with each other but grow in independent rates especially at higher temperatures. We also examine the structures of the lateral growth surfaces and find that the growth surfaces are locally flat and the Kossel mechanism of crystal growth seems to be operative. In addition, the fold surfaces are found to be covered with relatively short
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chain-folds ; at least about 60-70% of the folds are connecting the nearest or the next nearest neighbor crystalline stems. No appreciable bond orientational order is found in the undercooled melt of C_<100> and C_<1000>.
(2) Molecular dynamics simulation of fiber formation from oriented amorphous state Polymer crystallization from a uniaxially stretched amorphous state was investigated by molecular dynamics simulation using a realistic molecular model of poly (ethylene). Simulations for crystallization were performed at temperatures between 280 and 350K, and. structure formations to crystalline states having lower symmetry than the hexagonal phase of poly (ethylene) were realized above 300 K. It is found that all of order parameters considered to analyze the crystallization process show the same time dependence at a given temperature: there is no precursor prior to crystallization. The temperature dependence of the crystallization rate has a bell-shape and a maximum of the crystallization rate appears around 325 K. Less
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