1987 Fiscal Year Final Research Report Summary
Time Evolution of Domain Structure in First-Order Transition
| Project/Area Number |
61460030
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性
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| Research Institution | Kyoto University |
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Principal Investigator |
MIYAJI Hideki Kyoto University, 理学部, 助教授 (90025388)
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| Project Period (FY) |
1986 – 1987
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| Keywords | First order transition / Domain structure / Interface / fractalSpherulite / X-ray smallangle seattering / Light scattering / 光散乱 / 高分子 |
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| Research Abstract |
First-order transition accompanies the discontinuous change in order parameters; for example, density changes abruptly at the boundary of two phases. The region surrounded by the boundary is called domain. The time evolution of the domain was studied on the crystal growth of polymers. The glass of isotactic polypropylene was warmed to form seectic phase and monoclinic phase successively on heating . Electron microscopy revealed that the crystallite was spherical nodule of a few tens nm in diameter. In small angle X-ray scattering , the scattered intensity increases and the scattering angle of the intensity maximum decreases on heating process; the growth of the domain was confirmed. Whether the boundary of the domains is smooth or rough is an important issue in growth mechanism of the domains. We performed small angle X-ray scattering in a wide range of scattering angle covering Porod's region. The nodular polypropylene was found to be fractal. Furthermore, the folded chain crystals and the extended chain crystalswere found to have the fractal surface. The concept of fractals has thrown a new light on the theory of crystal growth of polymers. We also performed light scattering on spherulite structure developed in supercooled melt. The result showed that in the dimension of several nm the spherulite was a sphere in which uni-axial crystallites developed radially. Therefore we can apply Avrami's equation and the theory of Sekimoto.
Crystallization from highly supercooled solution was studied on polystyrene; molecular weight dependence of crystallization rate and thickness of lamellar crystals was analyzed on a theory based on rough-surface growth.
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