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Thermal properties and isothermal crystallization of syndiotactic polypropylenes: Differential scanning calorimetry and overall crystallization kinetics
Author(s) -
Supaphol Pitt,
Spruiell Joseph E.
Publication year - 2000
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(20000103)75:1<44::aid-app6>3.0.co;2-1
Subject(s) - differential scanning calorimetry , crystallization , tacticity , materials science , polypropylene , isothermal process , kinetics , melting point , recrystallization (geology) , thermal analysis , atmospheric temperature range , thermodynamics , polymer chemistry , chemical engineering , composite material , thermal , polymerization , polymer , geology , paleontology , physics , quantum mechanics , engineering
Isothermal crystallization and subsequent melting behavior of five samples of syndiotactic polypropylene are presented. Crystallization studies were carried out in the temperature range of 60°C to 97.5°C using a differential scanning calorimeter (DSC). Subsequent DSC scans of isothermally crystallized samples exhibited double melting endotherms. The high melting peak was concluded to be the result of the melting of crystals formed by recrystallization during the reheating process. Overall crystallization kinetics was studied based on the traditional Avrami analysis. Analysis of crystallization times based on the modified growth rate theory suggested that, within the crystallization temperature range studied, the syndiotactic polypropylenes crystallize in regime III. Kinetic crystallizability parameters also were evaluated, and were found to be in the range of 0.41°C s −1 to 2.14°C s −1 . © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 44–59, 2000