Regensburg 2010 – scientific programme
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SYMR: Symposium Nuclear Magnetic Resonance: from Applications in Condensed-Matter Physics to New Frontiers
SYMR 5: Nuclear Magnetic Resonance: Frontiers and Applications
SYMR 5.4: Talk
Tuesday, March 23, 2010, 14:30–14:45, H48
Polymers under mechanical stress- an NMR investigation — •Ute Böhme1, Bo Xu2, Johannes Leisen2, Haskell W. Beckham2, and Ulrich Scheler1 — 1Leibniz Institute of Polymer Research Dresden — 2Georgia Institute of Technology, Atlanta, Georgia
Low-field NMR using permanent magnets in Halbach arrangements permit NMR investigation without the limits present in high-field NMR. The lower field in conjunction with confined stray field permit the application of NMR, in particular relaxation NMR in a stretching apparatus and a rheometer [1,2]. Crystalline and amorphous fraction of semi-crystalline polymers are distinguished by their transverse relaxation times. Upon mechanical load the relaxation times of the amorphous fraction changes as seen in in-situ measurements on polypropylene rods. During the formation of a neck the crystalline fraction becomes more prominent.
[1] S. Kahle et.al., KGK- Kautschuk Gummi Kunststoffe 61 (2008), 92.
[2] G. Mazzanti et.al., J. Am. Oil Chem. Soc. 85 (2008), 405.