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Response of polymers to external mechanical forces

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Low-field NMR based on in-house built Halbach magnets with Tecmag NMR spectrometers is used to study the effect of uniaxial mechanical stress on the polymer dynamics via NMR relaxation and double quantum experiments in an in-house built stretching apparatus.

Stretching apparatus including the Halbach magnet for in-situ NMR investigation while loading the sample

To study the effect of shear flow on polymers rheo NMR in a Couette cell or a cone-and-plate cell is used. A dedicated in-house built probe head permits the study of polymer melts up to 250°C. It can be used to study the effect of shear on the polymer dynamics as well as for flow imaging in a Couette cell.

Effect of shear on the polymer dynamics of a melt of poly(propylene) showing, that in this case the loss of entanglements dominates

Related publications

  • Böhme, U. ; Scheler, U.
    An NMR investigation of a polymer melt under shear
    in: NMR Spectroscopy of Polymers: Innovative Strategies for Complex Macromolecules, Cheng, H.N.; Asakura, T.; English, A.D., eds., ACS Publisher (2011) 1077, Chapter 26, 431-438
  • Böhme, U. ; Gelfert, K. ; Scheler, U.
    Solid-state NMR of polymers under mechanical stress
    AIP conference proceedings 1330 (2011) 109-112
  • Ohgo, K. ; Bagusat, F. ; Asakura, T. ; Scheler, U.
    Investigation of structural transition of regenerated silk fibroin aqueous solution by rheo-NMR spectroscopy
    Journal of the American Chemical Society 130 (2008) 4182-4186