1996 Fiscal Year Final Research Report Summary
Role of Topological Repulsive Forces in Polymer Crystallization
| Project/Area Number |
07651100
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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 |
高分子構造・物性(含繊維)
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| Research Institution | Fukui University |
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Principal Investigator |
IWATA Kazuyoshi Fukui Univ. , Dept.Applied Physics, professor, 工学部, 教授 (00020230)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Mitsuya Fukui Univ. , Dept.Applied Physics, assistant, 工学部, 教務員 (40227179)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Polymer Crystal / Topological Repulsive Force / Crystalline Ratio / Structure of Amorphous Phase / Entanglement / Computer Simulation / Local Knot |
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| Research Abstract |
In semi-crystalline polymers, ciystalline phase coexists with amorphous phase, but the nature of the latter has not yet been known well In this work, we propose a new hyposesis that, in crystallizing from melts, entanglements among polymers are expelled form the crystalline phase and accumulated into the amorphous phase, se that the free energy of the amorphous phase increases and ciystallization stops at point where driving force of ciystallization balances the increase of the free energy. To prove the hyposesis, we have performed computer simulations of amorphous polymers in which entanglements are highly condensed. As a model of such systems, permanently entangled cyclic polymers, which are usually called catena networks, are considered. Changing the concentration of entanglements, while keeping the entanglement state, the polymer number and the element concentration of the systems, the thermodynamic and mechanical properties of the systems are studied in relation to the crystallization of the polymers. The following are found.
1)The chemical potential of elements in the amorphous phase is computed numerically as function of the concentration of entanglements, and it is shown that the chemical potential comes from repulsive interaction among "local-knots".
2)With use of this chemical potential and the entropy of crystallization found in the literature, we have found a relation between the crystalline temperature and the ratio of crystalline phase, which explain well the known experimental results.
3)In the amorphous phase, polymer chains take an unusual conformation, which is normal in global scale, but highly extended locally.
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