| 研究課題/領域番号 |
19K03761
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| 研究機関 | 山形大学 |
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研究代表者 |
SUKUMARAN S.K. 山形大学, 大学院有機材料システム研究科, 准教授 (70598177)
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| 研究分担者 |
瀧本 淳一 山形大学, 大学院有機材料システム研究科, 教授 (50261714)
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| 研究期間 (年度) |
2019-04-01 – 2022-03-31
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| キーワード | Polymer Entanglements / Mixing Rule / Polymer Blends / Polymer Melts / Polymer Dynamics |
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| 研究実績の概要 |
We investigated blends of polymer chains exhibiting monomer size disparity (i.e., whose monomer (bead) sizes differ) at several blending ratios. Similarly to blends of polymers with differing chain stiffnesses, topological analysis by length minimization indicated that that the tube diameters of both types of chains calculated from the primitive path configurations were almost equal to each other. This lends further support to the prevailing wisdom that there is just "one" tube diameter in a polymer blend.
Interestingly, the composition dependence of these blends is essentially identical to that observed in experiments (Y. Matsumiya et al., Macromolecules 48, 7889 (2015)). It is germane to note that the experimental results are qualitatively different from theoretical expectations on the basis of extensions to the ansatz that work for monodisperse melts. The results suggest that the crucial factor behind the origin of the anomaly is the monomer size difference.
It is highly likely that the monomer size disparity leads to differences in local packing when compared to the packing in single component melts. This suggests that the anomalous dependence of the tube diameter on the composition could be related to the local monomer packing. We are currently exploring these ideas in greater detail.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
We had worked on a different aspects of polymer melts as part of an earlier project. Therefore we had some experience in dealing with the issues that could cause delays. On the basis of that experience, we had anticipated and were adequately prepared to tackle for most of the problematic issues that were likely to arise. Therefore, we were able to quickly address any issues that arose before they became big problems.
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| 今後の研究の推進方策 |
As mentioned earlier, we have been able to qualitatively reproduce the experimentally observed anomalous concentration dependence of the tube diameter. This has allowed us to attribute, at least tentatively, the origin of the observed anomaly to differences in the local monomer packing. Consequently, our next step will be to understand how differences in the local monomer packing lead to anomalous behaviour in these blends. Therefore, our current focus is on quantifying the local monomer structure. To this end, we have begun calculating the monomer-monomer pair correlation function which quantifies how the local density varies with the intermonomer distance. Preliminary results suggest that the pair correlation functions exhibit some differences in blends with monomer size disparity when compared to blends with chain stiffness disparity and in single component melts. We are currently further pursuing this line of investigation.
In addition, we are investigating the phase diagram of polymer blends with monomer size disparity as a function of the monomer repulsion by varying the appropriate parameter in the truncated shifted purely repulsive Lennard-Jones potential. This will allow us to investigate the effect of the intermolecular potential on the entanglement structure in blends.
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| 次年度使用額が生じた理由 |
Due to the current situation because of the corona virus, the following activities were affected: (1) An international workshop co-organized by the PI for the end of March had to cancelled. The co-PI had planned to use his travel budget for an extended stay around the time of the workshop for research collaboration. This is now planned for the coming year. (2) Due to difficulties at the vendor side, the purchase of a personal computer had to be postponed. That personal computer will be acquired this year. (3) Invitation to a collaborator for a research seminar and discussion regarding the research project had to be cancelled. It is hoped that the invitation will be possible in the coming year.
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