Effect of long branches on the rheology of polypropyleneEffect of long branches on the rheology of polypropylene Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2015-10-242004enIn order to study the rheology of long chain branched polymers, branches have been added on linear polypropylene precursors in varying amounts using reactive modification with peroxydicarbonates. The branched polypropylene samples show distinct strain hardening, something absent from the linear melt; this considerably improves the melt strength of the modified polymer. The zero shear viscosity and the elasticitymeasured by the relaxation spectrum also increase with the number of branches per molecule. Two models are applied to describe strain hardening of the viscosity during the course of elongation. The model parameters were found to vary systematically with the degree of branching and, therefore, their values can be used as a measure of this. Consequently, fluidity, elasticity, strain hardening, and melt strength are all related to the degree of long chain branching.http://creativecommons.org/licenses/by/4.0/Journal of Rheology484895-914 Gotsis Alexandros Γκοτσης Αλεξανδρος Zeevenhoven B. L. F. Tsenoglou, Christos, 1954- AIP Publishing Elasticity Polymere Polymeride Polymers and polymerization polymers polymere polymeride polymers and polymerization Molecular spectra Gases--Viscosity Internal friction (Liquids) Liquids--Viscosity viscosity gases viscosity internal friction liquids liquids viscosity