Berlin 2008 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 37: Molecular Dynamics

CPP 37.7: Vortrag

Freitag, 29. Februar 2008, 12:00–12:15, C 230

Chain motion in poly(ethylene oxide) crystallites as studied by NMR — Anja Achilles, Albrecht Petzold, Thomas Thurn-Albrecht, and •Kay Saalwachter — Institut für Physik, Martin-Luther-Universität Halle Wittenberg, 06099 Halle (Saale)

Many stereoregular polymers exhibit pronounced large-scale dynamics in the crystalline phase. “Helical-jump” processes mediate chain transport over large distances through the crystallites, and they are often related to the mechanically active α_(c) relaxation and macroscopic properties such as yield processes and ultradrawability. While the timescale of such processes has been studied for many different polymers [1], their dependence on morphological parameters, such as crystalline and amorphous layer thickness, has received less attention.

In this contribution, we report on NMR investigations of helical jumps in PEO crystallites, using advanced high-resolution ¹³C exchange spectroscopy as well as simple analyses of the ¹H time-domain signal. These results are correlated with SAXS-determined changes in the morphology and crystallinity as a function of molecular weight and the crystallization conditions.

[1] W.-G. Hu, K. Schmidt-Rohr, Acta Polym. 50, 271 (1999)