Effect of Branch Length on 13C NMR Relaxation Properties in Molten Poly[ethylene-co-(α-olefin)] Model Systems
✍ Scribed by Matthew Parkinson; Katja Klimke; Hans Wolfgang Spiess; Manfred Wilhelm
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 171 KB
- Volume
- 208
- Category
- Article
- ISSN
- 1022-1352
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
The potential of branch length discrimination for branches containing six and more carbons via bulk NMR relaxation properties in the melt‐state has been explored. A systematic increase in the ^13^C spin‐lattice relaxation time (T) of the terminal branch carbons 1 and 2 was observed when the branch increased from 6 to 16 carbons in length. The measurement of T via inversion recovery at high‐field showed the most reliable data. The effects of saturation and NOE were addressed by using recycle delays longer than 5 × T and the use of the saturation recovery was found to be unsatisfactory. All nuclear relaxation times were determined in a highly time efficient manner using a previously developed melt‐state MAS NMR method.
magnified image