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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 35: Poster Session II

CPP 35.27: Poster

Wednesday, March 29, 2023, 11:00–13:00, P1

Non-linear mechanical properties of polycaprolactone polymer/oligomer blends with defined entanglement density and crystalline thickness — •Tonghua Liu, Albrecht Petzold, and Thomas Thurn-Albrecht — Von-Danckelmann-Platz 3, 06120, Halle(Saale)

The mechanical properties of semi-crystalline polymers are determined by the semi-crystalline morphology and the entanglements in the amorphous regions. Here we use polymer/oligomer blends to control the entanglement density independently of the crystallinity. This system is also used as a model to study effects on the non-linear mechanical properties. The aim of the project is to develop a quantitative method for the determination of the entanglement density in the amorphous region as well as to investigate its relation to yielding, modulus and strain hardening. The commonly used method is tensile testing, but cavitation and necking cannot be avoided. Instead, we use plane-strain compression tests, which allow the direct determination of the true stress and avoids problems like cavitation. A separation of viscous and elastic contributions can be achieved by inserting relaxation measurements during the deformation. Our preliminary results indicate a strong effect of the crystallinity on the modulus and yield stress. The relation between strain hardening and entanglement density will be discussed.