Molecular Motion in Polypropylene, Isotactic and Atactic
- 1 October 1958
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 29 (10), 1438-1441
- https://doi.org/10.1063/1.1722964
Abstract
Molecular order and motion in isotactic and atactic polypropylene molecules have been studied by proton magnetic resonance methods over the temperature range 77–400°K, and by x‐ray diffraction. It is shown that some motion persists at the lowest temperatures, and becomes pronounced in the temperature interval 77–110°K. This behavior is ascribed to motion of the methyl groups about the threefold axis. The resonance undergoes further narrowing near room temperature for the atactic polymer, presumably owing to rotational and translational motions of chain segments. The isotactic compound possesses a narrow resonance superposed on a broad absorption over a wide temperature range. The former, ascribed to the amorphous regions, narrows at higher temperatures than for the atactic polymer, presumably owing to constraints imposed by the crystalline regions. The chains of the isotactic compound are less mobile than in polyethylene, as shown by the resonance studies and by x‐ray diffraction comparisons of the rate of crystallization.Keywords
This publication has 22 references indexed in Scilit:
- Molecular Motion in Polypropylene, Isotactic and AtacticThe Journal of Chemical Physics, 1958
- Diffusion in Ethylene Polymers. III. Effects of Temperature and PressureJournal of the American Chemical Society, 1958
- Molecular motion in polyethyleneJournal of Polymer Science, 1957
- Note on the degree of crystallinity in polymers as found by nuclear magnetic resonanceJournal of Polymer Science, 1957
- Nuclear Magnetic Relaxation in Polytetrafluoroethylene and PolyethyleneThe Journal of Chemical Physics, 1957
- Nuclear magnetic resonance absorption in polymethyl methacrylate and polymethyl α‐chloroacrylateJournal of Polymer Science, 1956
- On the morphology of highly crystalline polyethylenesJournal of Polymer Science, 1956
- Proton Magnetic Resonance in PolyamidesJournal of Applied Physics, 1955
- Nuclear magnetic resonance determination of degree of crystallinity in two polymersJournal of Polymer Science, 1953
- Crystalline Behavior of Linear Polyamides. Effect of Heat TreatmentJournal of the American Chemical Society, 1940