Regensburg 2007 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: POSTER: Polymer Physics
CPP 8.15: Poster
Montag, 26. März 2007, 16:00–18:00, Poster B
Adiabatic crystallization of polycaprolactone — •Andreas Wurm1, Yuji Miyazaki2, Kumiko Miwa2, Akira Inaba2, and Christoph Schick2 — 1University of Rostock, Institute of Physics, Polymerphysics, 18051 Rostock, Germany — 2The Research Center for Molecular Thermodynamics, Graduate School of Science, Osaka University TOYONAKA, OSAKA 560 0043 JAPAN
Existence and formation of pre-ordered structures as the initial step of polymer crystallization are discussed controversially. Most of the findings and interpretations are based on scattering experiments, which test small density differences between the assumed precursors of the crystals and the surrounding melt. Because of the low contrast the interpretation of experimental results becomes often speculative. Contrary relaxation experiments are probing motions in the sample and are therefore independent on density contrast. During crystallization material is transformed from the liquid to the solid state. Consequently, motions (fluctuations) typical for a liquid become impossible and do not longer contribute to the measured relaxing signal. For pre-ordered structures we expect some changes in mobility too because of the changes in conformation on pre-ordering. Adiabatic calorimetry is suitable to detect temperature changes in the sample, which can be related to crystallinities below one thousandth. In this study we compare crystallinity data from adiabatic calorimetry in the sub-percent range with complex dielectric permittivity of ε-polycaprolactone (PCL) during isothermal crystallization.