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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 24: Poster Session I

CPP 24.26: Poster

Montag, 16. März 2020, 17:30–19:30, P3

Effect of entanglements on the morphology and crystallinity of semi-crystalline polymer — •Zefan Wang, Mareen Schäfer, Albrecht Petzold, Thomas Thurn-Albrecht, and Kay Saalwächter — Institute for Physics, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle (Saale), Germany

Recent simulation work indicates that the thickness of crystalline lamellae in the semi-crystalline polymer might be controlled by the entanglement density of the crystallizing melt. However, experimental evidence of how the morphology and the crystallinity of the semi-crystalline polymer is influenced by the topological restriction of entanglement density is scarce. By diluting high molecular weight polycaprolactone (PCL) with its own oligomer, a series of PCL samples with different entanglement density in equilibrium were prepared. The reduced entanglement density in the melt state was confirmed by rheological measurements. In addition, after crystallization, the semicrystalline morphology was characterized by SAXS and solid state NMR. At low crystallization temperatures the long chain polymer and the oligomer cocrystallize. SAXS data indicate that the lamellar thickness remains constant while the thickness of the amorphous regions decreases with decreasing entanglement density in the melt state. NMR measurements confirmed the corresponding increase of the crystallinity. These observations suggest that the thickness of the amorphous regions and therefore also the of semicrystalline polymers is controlled by the entanglement density in the melt state.