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A Study of the Use of Oscillatory Flow to Characterize Isotactic and Syndiotactic Poly(propylene)s
Author(s) -
Rojo Elena,
Peña Begoña,
Muñoz Maria Eugenia,
Santamaría Anton
Publication year - 2006
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200600281
Subject(s) - tacticity , branching (polymer chemistry) , polymer chemistry , materials science , rheology , intrinsic viscosity , molar mass distribution , composite material , polymer , polymerization
Summary: A rheological characterization of poly(propylene)s (PP) of different tacticity, monomodal and bimodal molecular distribution and long chain branching (LCB), is presented. Loss factor δ plotted as a function of the complex modulus G * allows to discriminate syndiotactic from isotactic PPs, as well as syndiotactic monomodal from bimodal samples. However, using such rheological plots is not effective to investigate the broadness of the molecular weight distribution and other rheological techniques are proposed. Isotactic and syndiotactic PPs submitted to electro beam irradiation give rise to thermorheological complexity, associated to LCB. The degree of LCB is estimated using complex viscosity results. Syndiotactic poly(propylene)s are more prone to give long branches than isotactic samples.A symptom of long chain branching is detected in irradiated syndiotactic PPs.