Thermal diffusivity study of polystyrene/poly(vinyl methyl ether) blends by flash radiometry
| Autor: | Naoto Tsutsumi, Tsuyoshi Kiyotsukuri, Wataru Sakai, Shigenobu Kizu |
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| Rok vydání: | 1997 |
| Předmět: |
Cloud point
Polymers and Plastics Nucleation Analytical chemistry Condensed Matter Physics Thermal diffusivity Lower critical solution temperature Isothermal process chemistry.chemical_compound chemistry Polymer chemistry Materials Chemistry Polystyrene Polymer blend Physical and Theoretical Chemistry Phase diagram |
| Zdroj: | Journal of Polymer Science Part B: Polymer Physics. 35:1869-1876 |
| ISSN: | 1099-0488 0887-6266 |
| DOI: | 10.1002/(sici)1099-0488(19970915)35:12<1869::aid-polb2>3.0.co;2-l |
| Popis: | This article presents thermal diffusivity (D) measurements by flash radiometry for the polymer blend of polystyrene (PS) and poly(vinyl methyl ether) (PVME) with lower critical solution temperature (LCST) phase diagram. Dependence of D on PS content measured at 100°C coincides a phase diagram determined by a cloud point measurement. D value for the blend decreases with increasing PS content and has minimum value at the PS content around 20 wt % from which D increases again with increasing PS content. If the concentration fluctuation between two components in the miscible states at the temperature close to LCST causes the remarkable phonon scattering, the composition dependence of D would resemble the phase diagram. D for the sample in the phase-separated state is larger than that for the miscible state. The larger D in the phase-separated sample would be due to the decrease of the total surface area microscopically contacted to the counter component in the phase-separated state. Dependence of D on temperature for the phase-separated sample is quite different from that of the miscible one. On an isothermal measurement of D for PS/PVME (10 : 90) at 110°C just below the cloud point, D started to increase at time above 100 min and leveled out above 250 min. Isothermal observation of sample film by a differential interference contrast microscopy showed the creation of some structure due to the nucleation and growth of interface at 225 min and it became obvious above 250 min. Thus, the increase in D at 110°C implies that D can sensitively reflect the change in microscopic structures which follows the nucleation and growth of interface. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1869–1876, 1997 |
| Databáze: | OpenAIRE |
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