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CPP: Chemische Physik und Polymerphysik

CPP 29: POSTER: Polymer physics

CPP 29.69: Poster

Dienstag, 8. März 2005, 16:30–18:30, Poster TU D

Order Phenomena in s-PP Crystallization? — •Andreas Maus and Kay Saalwächter — Institut für Makromolekulare Chemie, Albert-Ludwigs-Universität Freiburg, Stefan Meier Str. 31, D-79104 Freiburg, Germany

We report on the crystallization behavior of syndiotactic polypropylene (s-PP), where the kinetic is highly influenced by the thermal history of the sample, primarily the temperature of the melt prior to cooling to the crystallization temperature, as was shown by dilatometry [1]. In our NMR experiments the isothermal crystallization process was observed via the analysis of the transverse relaxation function measured by applying a modified CPMG pulse sequence, including a magic-echo-sandwich (MSE) for quantitative evaluation of the crystallinity. In our measurements we reproduced this so called memory effect (self seeding) which occurs in many polymers, and could resolve subtler differences in the crystallization kinetics. Possible causes of the memory effect, which are assumed to be related to local order phenomena, are investigated using static ¹H multi quantum (MQ) and relaxation experiments.

[1] B. Heck, G. Strobl, Colloid Polym. Sci, 282, 511-513 (2004)