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Crystallization and melting behavior of 1,2‐syndiotactic polybutadiene
Author(s) -
Bertini Fabio,
Canetti Maurizio,
Ricci Giovanni
Publication year - 2004
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/app.20115
Subject(s) - polybutadiene , tacticity , crystallization , materials science , nucleation , differential scanning calorimetry , polymer chemistry , avrami equation , small angle x ray scattering , crystallization of polymers , isothermal process , kinetics , thermodynamics , polymer , copolymer , chemical engineering , composite material , polymerization , scattering , physics , quantum mechanics , optics , engineering
1,2‐Syndiotactic polybutadiene was synthesized at −30°C using the catalyst system CrCl 2 (dmpe) 2 ‐MAO. The syndiotactic index of the butadiene sequences, expressed as a percentage of syndiotactic pentads [rrrr], was evaluated by 13 C‐NMR measurements. WAXD and SAXS techniques were employed to characterize the crystalline structure of the polymer. The thermal behavior of the polybutadiene was investigated by differential scanning calorimetry. The isothermal crystallization kinetics were described by means of the Avrami equation, which suggested a three‐dimensional growth of crystalline units, developed by heterogeneous nucleation, followed by a secondary crystallization stage. Polybutadiene isothermally crystallizes from the melt according to regime II of crystallization described by Lauritzen–Hoffman secondary nucleation theory. Nonisothermal crystallization kinetics were elaborated using the Ziabicki and Avrami methods modified by Jeziorny. The equilibrium melting temperature was calculated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1680–1687, 2004