2001 Fiscal Year Final Research Report Summary
Development of Quantitative Evaluation on Molecular Aggregation in Polymeric Materials by Means of Dynamic Infrared Spectroscopy
| Project/Area Number |
11450370
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Kyoto Institute of Technology |
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Principal Investigator |
NOMURA Shunji Kyoto Institute of Technology, Faculty of Textile Science, Professor, 繊維学部, 教授 (10026073)
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| Project Period (FY) |
1999 – 2001
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| Keywords | Dynamic Infrared Spectroscopy / Infrared Absorption Dichroism / Segmented Poly(urethaneurea) / Molecular Motion / Molecular Aggregation / Spherulitic Structure |
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| Research Abstract |
First of all, after improvement of the optical system in our dynamic infrared (DIR) spectroscopic system, various kinds of machine constants in the optical system were measured in detail.
Second, static strain dependence of infrared absorption spectra in segmented poly(urethaneurea) (SPUU) were measured at wavenumber range of 1500 and 1800 cm^<-1>, where we got three kinds of absorption bands attributed to C=O stretching modes. These are assigned to the hydrogen-bonded and hydrogen-free urethane carbonyls in the soft segments, and hydrogen-bonded urea carbonyl in the hard segments. The strain dependence of peak positions, peak hights, and peak widths in three bands were analyzed in detail. By using these static data, the dynamic change of infrared spectra were simulated and compared with the dynamic data. As a result, it was confirmed that the dynamic change in film thickness could be similar to the deformation under constant volume.
Finally, the in-phase components in dynamic infrared s
… More
pectra of SPUU give the positive orientation of the soft segments and the negative orientation of the hard segments. The out-of-phase components of the urea carbonyl groups at -10℃ give the dynamic peak shift of the opposite directions for the parallel and perpendicular polarizations along the strain axis.
The relative static and dynamic dichroic difference spectra normalized by the peak height of the urea band are in good agreement except at a lower wavenumber than that at the urea band. On the other hand, the same normalized spectra for the average absorbances give the clear difference between the soft and hard segments. It is derived from this difference that the hydrogen bonds of the urea carbonyl are broken by the dynamic strain along the bonding.
From the above discussion on the similarity between the static and dynamic dichroic difference spectra and the difference between the static and dynamic average absorption spectra, it is concluded that stress along the urea carbonyl bonds, but not along the polymer chains, takes an important role on the orientation of the hard segment domains. That is, the soft segments as a matrix component orient toward the strain direction, however the hard segments make perpendicular orientation to the strain axis due to the stress along the urea carbonyl bond, which is perpendicular to the hard segment chain. Less
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