Abstract
2H-NMR experiments were performed on deuterated, gel-drawn ultrahigh molecular weight polyethylene in order to obtain information about the orientational distribution and the molecular mobility. An increase of the spinlattice relaxation time by about an order of magnitude was observed in comparison to melt crystallized polyethylene indicating high perfection of the fibrillar crystallites. Beside the 2H-NMR resonance for a highly ordered rigid component (orthorhmobic or monoclinic fibrillar crystallites) a highly oriented mobile and a little oriented mobile component was observed. The latter can be assigned to constrained noncrystalline chain segments. Saturation-spin echo pulse experiments showed a continuous transition in the T1 time of the oriented components. Variations in the line shape can be explained by a dynamic equilibrium of all-trans conformations and >2% gauche conformations in extended chain segments. The oriented mobile segments may be assigned to areas of the crystallites in which trapped conformational defects are concentrated.
| Original language | English |
|---|---|
| Title of host publication | Integration of Fundamental Polymer Science and Technology—5 |
| Editors | P.J. Lemstra, L.A. Kleintjens |
| Place of Publication | Amsterdam |
| Publisher | Springer |
| Pages | 276-290 |
| Number of pages | 15 |
| ISBN (Electronic) | 978-94-011-3890-1 |
| ISBN (Print) | 978-94-010-5732-5, 978-1-85166-587-7 |
| DOIs | |
| Publication status | Published - 1991 |
Keywords
- Quadrupolar splitting
- Draw ratio
- Ultrahigh molecular weight polyethylene
- Crystalline component
- Gauche conformation