| Budget Amount *help |
¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 1996: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1995: ¥4,100,000 (Direct Cost: ¥4,100,000)
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| Research Abstract |
Almost all molecules including chain polymers, are anisotropic in shape at a molecular or segmental level. Shape anisotropy brings about anisotropy in intermolecular interactions, and this causes various co-operative phenomena that cannot be observed in systems of symmetrical molecules. In this research project, we studied theoretically and experimentally the effects of a uniaxial stretch applied to a blend of two polymers on their segmental orientations and miscibility.
The theory, based on a lattice model, predicted that the excluded volume effect would induce extra orientations of the two components and either increase or decrease miscibility, depending on the flexibility of the two polymers.
Polystirene (PS) /polyvinylmethylether (PVME) and poly (alpha-methylstirene) (PMS) /PVME blends as models for a mixture of two flexible polymers and blends of EBBA (a liquid crystalline rigid molecule) and EPR ( ethylene propylene rubber) as models for a rigid polymer/flexible polymer mixture were studied by infrared dichroism spectroscopy, laser light scattering and fluorescence spectroscopy. The results confirmed the theoretical predictions. In particular, the theory and experiments commonly showed that when the two components are flexible polymers, a uniaxial stretch induces immiscibility of the blend, while it enhances miscibility of a flexible polymer with a rigid (highly asymmetric) molecule.
These results stress the importance of excluded-volume or entropic interactions in understanding the behavior of condensed polymer systems under deformation.
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