| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1991: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1990: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
The Purposes of this work are :
1) Investigation of the self organization process in binary Polymer blends irradiated with UV light.
2) Elucidation of the possibility for taking advantage of this mechanism to design novel polyner materials with the ordered structures in micrometer range.
At first, Polystyrene/poly(2-chlorostyrene)(PS/P2CS)and polystyrene/poly(vinyl methyl ether)(PS/PVME)blends were irradiated during the time evolution of the spinodal decomposition Process. The photo-cross-link reactions between PS chains are induced via the photodimerization of anthracene moieties which are covalently attached to PS chains. The effects of irradiation intensity, irradiation time, annealing temperature and T-jump depths on the resulting morphology were examined by using phase-contrast optical microscope, light scattering and small-angle X-ray scattering.
The following results were obtained :
- The concentration fluctuations developing during the spinodal decomposition process were efficiently
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frozen upon irradiation with either XeF excimer laser or ffg lamp. These results indicate that by taking advantage of photo-cross-link reactions, multiphase polymer materials with various ordered structures in the mum range can be designed.
- Further analysis of the ordered structures resulting from irradiation shows that the reaction between PS does not only freeze the concentration fluctuations but also modify these structures. 'For PS/P2CS submitted to a shallow T-jump, the light scattering profile exhibits multiple scattering peaks, revealing the unusual effects of irradiation.
- To separate the contribution of the spinodal structures to the effects of. photo-cross-link, irradiation experiments were performed in the one-phase region of Polystyrene/polybutadiene(PS/PB). It was found that photo-cross-link reactions between PB chains result in the large modulated structures with internal domains
- A reaction-diffusion model taking into account of the nonlinear reactions between polymer chains in a binary polymer mixture was proposed in ordered to explain these morphology. Alternatively, there is another possibility for the origin of the ordered structures revealed by irradiation with laser, That is the convection caused by the extra heat originated from the radiationless process of'excited anthracenes. Actually, the morphology obtained by irradiating PSA/P2CS blends with XeF excimer laser shows the typical dissipative structures of the Rayleigh-Benard type.
The competition between reaction-diffusion Turing instability and Rayleigh-Benard instability for polymer alloys irradiated with light is currently investigated by computer simulation. Less
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