Dresden 2003 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 20: POSTER A
CPP 20.7: Poster
Montag, 24. März 2003, 19:00–21:00, ZEU/250
SANS study of non-linear relaxation mechanisms in an elongated polymer melt — •Ariane Blanchard1, Wim Pyckhout-Hintzen1, Dieter Richter1, and Ekkehard Straube2 — 1Institut für Festkörperforschung, Forschungszentrum Jülich — 2Martin-Luther-Universität, Halle-Wittenberg
Small angle neutron scattering experiments on quenched
partially deuterated uniaxially deformed polyisoprene
melts will be presented. This study sheds new light on
the until now unobserved but expected chain retraction
after a fast step strain. The dynamic processes of end
retraction, contour length fluctuations and eventually
reptation can be conveniently analyzed in a home-built
melt elongational rheometer.
The microscopic time of the chains is decoupled from the
neutron measurement time by the quench. The time-temperature
superposition principle was applied throughout the analysis
for which data were obtained from linear shear melt rheology
at different temperatures. The extended state before
relaxation as well as the later annealing times (0.1 up
to 30 times the Rouse time) were frozen in and studied
in the 2 dimensional detector plane as well as anisotropically
along the elongation and perpendicular strain direction.
A clear proof of the mechanisms is found and an interpretation in terms of the tube model is foreseen.