Dresden 2017 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 40: Focus: Polymer Crystallization - from Model Systems to New Materials II
CPP 40.2: Vortrag
Mittwoch, 22. März 2017, 15:30–15:45, ZEU 222
Thermally induced shape-memory actuators on the basis of crosslinked poly(ε-caprolactone) — •Oleksandr Dolynchuk1, Igor Kolesov2, Dieter Jehnichen1, Hans-Joachim Radusch2, and Jens-Uwe Sommer1,3 — 1Leibniz-Institut für Polymerforschung Dresden e.V., Germany — 2Martin Luther University Halle-Wittenberg, Center of Engineering Sciences, Germany — 3Technische Universität Dresden, Institute for Theoretical Physics, Germany
Polymer materials capable of active motion in response to external stimuli have an outstanding potential for numerous applications from space engineering to smart bioimplants, nanostructures etc. The evolution of the thermally induced invertible shape-memory effect (SME) under constant load was investigated in crosslinked linear poly(ε-caprolactone) (PCL). The viscoelastic and thermal properties as well as morphology, size, and orientation of crystals in PCL networks were analyzed as well. In addition, PCL with the highest achieved crosslink density revealed remarkable invertible actuation under stress-free conditions. The oriented growth of crystals was found to be the origin of the invertible SME under and without load. The mean field approach was used to calculate the free energy change during non-isothermal crystallization of PCL networks under load, whereby the possible morphology and orientation of crystals were analyzed. The analytical results on the nanocrystalline structure along with fitting curves of strain vs. temperature, which were got by modeling the SME in PCL under load, correspond well to the experimental outcomes.