Chain Folding of Semicrystalline Polymers

Toshikazu Miyoshi

Department of Polymer Science, The University of Akron, Akron, Ohio 44325, USA

There is a long-standing controversy about chain-folding structure and mechanism of long polymer chains during crystallization. This information is a key factor to understand the crystallization mechanisms at the molecular levels. Recently, solid-state (SS) NMR combined with selectively 13C isotopic labelling has been successfully utilized to determine local chain trajectory of folded polymer chains in single and bulk crystals.1-6 In this talk, we will discuss various physical effects on chain folding and crystallization mechanisms of several polymers such as Poly(L-Lactic, Acid),1, 2 Isotactic-poly(1-butene),1, 3, 4 and Isotactic-Polypropylene.1, 5, 6

1) Hong, Y.-l.; M.T.; et al, “Chain Trajectory of Semicrystalline Polymers As Revealed by Solid-State NMR Spectroscopy” ACS Macro Lett., 5, 355–358, 2016. (link)
2) Chen W.; MT.; et al, “Molecular Structural Basis for Stereocomplex Formation of Poly(Lactide)s in Dilute Solution” ACS Macro Lett., 4, 1264–1267, 2015. (link)
3) Hong, Y.-l.; M.T.; et al, “Three-Dimensional Conformation of Folded Polymers in Single Crystals” Phys. Rev. Lett., , 115, 168301, 2015. (link)
4) Hong, Y-l.; M.T.; et al, “Chain Trajectory and Crystallization Mechanism of Semicrystalline Polymer in Melt- and Solution-Grown Crystals as Studied by 13C-13C Double Quantum NMR” Macromolecules 48, 3282–3293, 2015. (link)
5) Yuan, S., M.T.; et al, “Folding of Polymer Chains in the Early Stage of Crystallization” ACS Maco Lett., 4, 1382–1385, 2015. (link)
6) Li, Z.; M.T.; et al, “Determination of Chain Folding Strcutre of Isotactic-Polypropylene Melt-Grown α Crystals by 13C-13C Double Quantum NMR and Selective Isotopic Labeling” Macromolecules 48, 5752–5760, 2015. (link)