NMR investigations of dynamics in the different phases of semicrystalline polymers

M. Schäfer, R. Kurz, A. Seidlitz, T. Thurn-Albrecht and K. Saalwächter

Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle (Saale), Germany

The melt-crystallized morphology of semicrystalline polymers strongly depends on the diverse dynamics in the amorphous and crystalline region. The connections between structure formation and dynamics of polymer chains are investigated with SAXS and NMR spectroscopy, respectively, comparing polymers with and without intracrystalline dynamics (crystal-mobile and crystal-fixed). Proton time-domain techniques enable the analysis of the phase components, the intracrystalline and the amorphous phase dynamics. The intracrystalline motion displays only a weak dependence on morphology [1]. SAXS results show, that the morphology of the crystal-fixed polymer, poly-ε-caprolactone (PCL), and the crystal-mobile polymer, polyethylene oxide (PEO), are qualitatively different [2]. The crystal thicknesses in PCL are well-defined, whereas in PEO a crystal reorganization process caused by the intracrystalline dynamics leads to a uniform amorphous region [2].
To investigate the impact of the crystalline growth and reorganization process on the morphology separately, polymers with slower intracrystalline mobility, e.g. polyoxymehtylene (POM), will be investigated. Further investigations address the relationship between morphology and entangled dynamics in the amorphous phase.

[1] R. Kurz, A. Achilles, W. Chen, M. Schäfer, A. Seidlitz, Y. Golitsyn, J.  Kressler, W. Paul, G. Hempel, T. Miyoshi, T. Thurn-Albrecht, and K. Saalwächter. Macromolecules 2017, 50, 3890-3902.  (link)
[2] A. Seidlitz. 2016. “Einfluss von Kristallisationskinetik und Dynamik im Kristall und in der Schmelze auf die Strukturbildung teilkristalliner Polymere.” Dissertation, Martin-Luther-Universtität Halle-Wittenberg.  (link)