Dresden 2020 – wissenschaftliches Programm
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CPP 95.1: Vortrag
Donnerstag, 19. März 2020, 15:00–15:15, ZEU 222
Confined Glassy Dynamics in a Star-Shaped Polymer Induced by Crystallization: Case study of Polyhedral Oligomeric Polysilesquioxane - Isotactic Polystyrene (POSS-iPS) — •Martin Treß1, Arthur Markus Anton1, Maximilian Vielhauer2, Pierre Lutz3, Rolf Mülhaupt2, and Friedrich Kremer1 — 1Universität Leipzig — 2Universität Freiburg — 3University Strasbourgh, France
In semi-crystalline polymers, segmental motion is often constrained. While segments far away from the crystallites have unperturbed dynamics (mobile amorphous fraction), the segments in their proximity move significantly slower (rigid amorphous fraction). Here, we present a study combining broadband dielectric spectroscopy (BDS) and Fourier transform infrared spectroscopy (FTIR) which reveals the opposite effect in a star-shaped polymer, namely a faster mean relaxation time of the amorphous part in the semi-crystalline state . A decomposition of the respective relaxation time distributions yields three fractions of different dynamics. These are assigned to a rigid amorphous fraction around the crystallites, a mobile amorphous fraction, and a confined amorphous fraction of enhanced dynamics presumably located around the POSS centers. Complementary FTIR measurements can address crystalline and amorphous moieties and trace their temperature dependence. These data sets give insight into the mechanism how the combination of crystallites and a star-like architecture constrains the dynamics in a way resembling spatial confinement.
 Tress et al. Macromolecules 51 (2018) 501-511