## Abstract The kinetics of the isothermal and nonisothermal cold crystallization of syndiotactic polystyrene (sโPS) were characterized with differential scanning calorimetry. A JohnsonโMehlโAvrami analysis of the isothermal experiments indicated that the cold crystallization of sโPS at a constant
Two-phase crystallization kinetics of syndiotactic polystyrene
โ Scribed by Andrea Sorrentino; Roberto Pantani; Giuseppe Titomanlio
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 560 KB
- Volume
- 48
- Category
- Article
- ISSN
- 0887-6266
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โฆ Synopsis
Abstract
In this work, a two phase crystallization model based on the extension of the Kolmogoroff approach was proposed and verified by comparison with experimental isothermal and nonisothermal crystallization data of Syndiotactic Polystyrene (sPS) in a very wide range of cooling rates, up to 600 ยฐC/s. To investigate the effects of high cooling rate on the sPS crystalline structure, a homemade apparatus was adopted. The morphology in solid samples was analyzed by densitometry, IR spectroscopy, and Xโrays diffraction. The coupling of these techniques allows the determination of the fractions of different crystalline phases. In agreement with meltโcrystallization studies of sPS proposed by different authors, either ฮฑ and ฮฒ forms could be produced depending on the thermal history of the sample. Results show that the stable ฮฒ form is favored for specimens solidified at higher temperature or under low cooling rates, whereas ฮฑ and mesomorphic forms are favoured at low temperature or high cooling rates. The proposed multiphase crystallization kinetics model successfully described all the range of experimental data. ยฉ 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1757โ1766, 2010
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## Abstract Analyses of the isothermal and nonisothermal melt kinetics for syndiotactic polystyrene have been performed with differential scanning calorimetry, and several kinetic analyses have been used to describe the crystallization process. The regime IIโIII transition, at a crystallization tem
## Abstract Meltingโpoint and spherulite growth rate measurements for a sample of syndiotactic polypropylene (__S__ = 0.716 and ฮท = 0.356) were analyzed for the parameters characterizing crystal formation and growth: __T__~__m__~ = 159 ยฑ 2ยฐC, ฯ~__e__~ = 47 erg cm ^โ2^, ฯ = 4.4 erg cm^โ2^, and __q__