Berlin 2015 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 21: Polymer dynamics

CPP 21.9: Vortrag

Dienstag, 17. März 2015, 11:45–12:00, C 264

Shear-induced ordering or disentaglement? — •Ulrich Scheler — Leibniz-Institut für Polymerforschung Dresden e.V.

Rheo NMR permits the investigation of molecular dynamics in a wide range of correlation times of polymer melts or solutions under shear in a Couette cell. transverse relaxation T2 is strongly affected by the slow dynamics of polymer chain segments. One would expect a strong shortening of T2 as a result of shear-induced ordering of the polymer chains in a Couette cell. However the opposite is observed T2 becomes longer in melts of poly(propylene) and solutions of poly(styrene sulfonate), which can be explained by a loss of entanglements as a result of the shear.