Regensburg 2002 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 3: Poster: Kristalline Polymere

CPP 3.2: Poster

Monday, March 11, 2002, 13:30–15:00, B

THERMAL STABILITY OF CRYSTALS DURING POLYMER CRYSTALLIZATION — •Andreas Wurm, Ragab Soliman, and Christoph Schick — Universität Rostock, Fachbereich Physik, Universitätsplatz 3, 18051 Rostock

In classic theories of polymer crystallization it is assumed that only the nuclei are in thermodynamic equilibrium with the melt. In Strobls model for polymer crystallization a multi-step process is discussed. At the first intermediate states the growing lamellar crystallites are considered to be in equilibrium with the melt. After a stabilization step the lamella gains final stability. In this poster we address the questions of the first stages of crystallisation and a possible stabilisation process of the lamella during isothermal crystallisation with time.

We have studied with dynamic mechanical and calorimetric measurements the stability of the growing polymer lamella by short pulse heating to different temperatures below the final melting temperature. The presented results confirm the existence of a stabilisation process. A possibility to quantify the stabilisation will be shown. This opens the chance to discuss the kinetics of stabilisation for PCL and sPP.

From dielectric measurements during isothermal crystallisation we obtained information about changes of the relaxation processes as well as changes of the conductivity. We discuss this changes, specially during the first stages of polymer crystallisation, in the background of Strobls model.