Phase-Transitional Behavior in Vinylidene Fluoride–Trifluoroethylene Copolymer Crystals
| Autor: | Rei Iwata, Shuichiro Miyata, Yoshinobu Kawasaki, Teruaki Yanagisawa, Yasuo Saruyama, Takashi Itoh |
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| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | Journal of the Physical Society of Japan. 73:1793-1797 |
| ISSN: | 1347-4073 0031-9015 |
| DOI: | 10.1143/jpsj.73.1793 |
| Popis: | The thermal and structural properties at normal and high pressures of vinylidene fluoride–trifluoroethylene (VDF/TrFE) copolymer crystals with VDF molar contents between 59 and 77% are examined using several types of thermal analysis systems as well as X-ray measurement. Although temperature changes in the crystal structures transform from a continuous [cooled phase (CP) to high-temperature phase (HP)] to a discontinuous one [low-temperature phase (LP) to HP] with increasing VDF molar content or external pressure for 65% VDF sample, the second-order phase transition does not appear but the transition from CP to LP occurs prior to the first-order phase transition from LP to HP. The sample with 65% VDF is composed of only CP, and LP suddenly appears in the 68% VDF sample and another LP is expected to exist in 71 and 77% VDF samples. The percolation theory may be used to explain such structural transformation which is very sensitive to VDF content. |
| Databáze: | OpenAIRE |
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