Berlin 2005 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 29: POSTER: Polymer physics

CPP 29.40: Poster

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

High precision light attenuation measurementsas a tool for studying the initial stagesof polymer crystallization — •Jens Fritsch, Werner Stille, and Gerd Strobl — Physikalisches Institut, Albert-Ludwigs-Universität Freiburg 79104 Freiburg, Germany

Investigating the crystallization kinetics of polymers, a variety of experimental approaches are applied. Although based on different properties there is not much difference in the sensitivity of all these methods. Reliable data are only obtained over a dynamic range of one to two orders of magnitude. Searching for an experimental tool with a higher sensitivity we found that measurements of the light attenuation coefficient can have a much larger dynamic range. We achieve the higher sensitivity with a self constructed measuring device which uses a modulated laser light source together with lock-in signal detection. For a data evaluation during the initial stages of polymer crystallization known relationships describing the dependance of the linear attenuation coefficient on the radius and the index of refraction of the growing objects can be used. We now are able to observe the crystallization process of polymers samples over a dynamic range of about four orders of magnitude and will report first results obtained for poly(ethylene-co-octene)s, s-polypropylene and poly(epsilon-caprolactone).