2015 Fiscal Year Research-status Report
Unified View of Entanglements in Polymer Liquids
| Project/Area Number |
26800221
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| Research Institution | Yamagata University |
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Principal Investigator |
SUKUMARAN S.K. 山形大学, 理工学研究科, 准教授 (70598177)
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Keywords | Entanglements / Polymer Blends / Polymer Melts / Polymer Solutions / Polymer Dynamics |
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| Outline of Annual Research Achievements |
Topological Analysis by length minimization on stiff/flexible blends at different blending ratios and two different combinations of chain stiffness values indicated that that the tube diameters of both the stiff and the flexible chains calculated from the primitive path configurations were almost equal to each other. To connect the entanglement physics of binary blends to single component melts, we have extended the entanglement models for melts of binary blends. The models shed light on the reason for a single tube diameter in blends and the results were in general agreement with the mixing rules obtained from two of the entanglement models. However, strong discrepancy exists between the results of the simulations and experimental data. The origin of the discrepancy is currently unclear.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
Several blends of flexible and stiff chains (N=200, different stiffness combinations) have already been investigated. To eliminate artifacts due to finite size effects, similar blends for N=300 are currently being studied. As the longest relaxation time of the N=300 blends are significantly longer than that of the N=200 blends, equilibration is time consuming.
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| Strategy for Future Research Activity |
We will continue to prepare well-equilibriated configurations of the blends of chains of different stiffness values for various molecular weights of the chains, perform topological analysis on the blend configurations that have been prepared, calculate the linear rheology of the well-equilibriated binary blends using the simulations and develop theoretical models to elucidate the nature of entanglements in binary blends.
As mentioned earlier, there is significant discrepancy between the results of rheological experiments and the results of simulations. In order to understand the discrepancy with the experimental results, we are also currently attempting to study blends with the same number of beads and same stiffness values but different monomer sizes. We plan to first equilibrate the configurations and then perform topological analysis on the equilibrated configurations. The results will be compared to the extended models and mixing rules derived earlier.
The simulations mentioned above are significantly more challenging than the simulations performed earlier. However, if successful, these simulations are likely to shed light on the discrepancy between experimental results and simulation results mentioned earlier. Such insight into the entanglement physics in blends especially with reference to experimental systems is unlikely to be obtained by other means.
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| Causes of Carryover |
In the first year, the equipment cost was higher than anticipated. To be on the safer side, I curtailed my personnel expenditure and travel costs. Therefore, I used part of the travel costs in the second year and hope to use the remaining amount in the next few months.
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| Expenditure Plan for Carryover Budget |
Travel Expense, Miscellaneous (mainly, publication costs)
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