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Correlation between Conformational Parameters and Rheological Properties of Molten Syndiotactic Polypropylenes
Author(s) -
Rojo Elena,
Muñoz Maria Eugenia,
Santamaría Anton,
Peña Begoña
Publication year - 2004
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200400138
Subject(s) - reptation , rheology , viscoelasticity , materials science , tacticity , thermodynamics , viscosity , rheometry , relaxation (psychology) , polymer chemistry , composite material , polymer , physics , polymerization , psychology , social psychology
Summary: New rheological results with molten polypropylenes of different degrees of syndiotacticity are presented. The temperature dependence of their dynamic viscoelastic functions is correlated with the characteristic ratio. Relaxation time and Newtonian viscosity values are plotted as a function of molecular weight. The very high values of both rheological parameters found for the most syndiotactic polypropylenes are explained considering the reptation model, which links conformational parameters with the viscoelastic response in the molten state.Disengagement or reptation time as a function of molecular weight.