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Correlation between Conformational Parameters and Rheological Properties of Molten Syndiotactic Polypropylenes

✍ Scribed by Elena Rojo; Maria Eugenia Muñoz; Anton Santamaría; Begoña Peña

Publisher
John Wiley and Sons
Year
2004
Tongue
English
Weight
114 KB
Volume
25
Category
Article
ISSN
1022-1336

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✦ Synopsis

Abstract

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.

magnified imageDisengagement or reptation time as a function of molecular weight.

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