Relaxation of shish-kebab precursor in isotactic polystyrene after short-term shear flow
✍ Scribed by Yunfeng Zhao; Go Matsuba; Koji Nishida; Tetsuaki Fujiwara; Rintaro Inoue; Inga Polec; Cong Deng; Toshiji Kanaya
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 958 KB
- Volume
- 49
- Category
- Article
- ISSN
- 0887-6266
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✦ Synopsis
Abstract
We studied the formation and relaxation of precursors of shish‐kebab in isotactic polystyrene after applying pulse shear flow at temperatures above the nominal melting temperatures T~m~ (=223 °C). It was found that the string‐like objects that were assigned to precursors in a previous article appeared in micrometer scale up to ∼285 °C, which was very close to the equilibrium melting temperature T (=289 °C), and the length and the diameter showed two‐step decays consisting of the fast and slow (almost nondecaying) components below ∼270 °C, whereas the slow component disappeared above ∼270 °C, suggesting that some mechanism stabilizing the string‐like objects disappeared at ∼270 °C. It was also found that the two‐step decay was a nature of a single string‐like object, but not an average nature of many precursors, showing heterogeneous inner structure of the precursor. We discussed a possibility that the string‐like object had a fringed micelle type structure including large crystals with a melting temperature of ∼270 °C. Within the proposed picture, the highest temperature for the precursor formation (∼285 °C) was explained as a melting of the large crystals in oriented melt. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010