Motion in polybutadiene near the Glass transition detected using NMR
Abstract
Experimental Studies have been made on the NMR transverse relaxation of deuterated polybutadiene of molecular weight 135000 as a function of temperature. At room temperature it is shown from NMR experiments on polybutadiene chains below the entanglement molecular weight that the polymer may be considered in terms of Rouse segments with approx 8 monomers/Rouse unit. Studies have been carried out on a sample of 135000 molecular weight comprising approximately 70 entanglement sections. These entangled chains naturally form a hierarchical structure. The NMR properties of a general, multi-level, hierarchical structure have been theoretically investigated in order to discover the effect on the transverse relaxation. Using this analysis the original room temperature Rouse and entanglement structure of polybutadiene was found and in this present work is extended to lower temperatures. As the temperature is lowered, progressive levels of the hierarchy dynamics are quenched. The spatial scale over which Rouse modes are still dynamically active descreases linearly as (T-T0)
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1998
- Bibcode:
- 1998APS..MARO38105A