Visualization of immobilization in shear bands by NMR imaging


  • The authors thank Dr. A. Karbach, Bayer AG, for providing the PC, Dr. T. Pakula and J. Vennemann for the drawing of the sample, and Dr. S. Hafner for helpful discussions. F. W. acknowledges a stipend of the “Studienstiftung des deutschen Volkes”.


A new 1H-NMR imaging method, in which the relaxation time provides the contrast, is demonstrated to be suitable for investigating the effect of shear bands—strongly localized inhomogeneities of the plastic deformation—on the local mobility of polymeric materials in the solid state. The immobilization of a shear band in cold-drawn polycarbonate (PC) is visualized for the first time. In addition to a description of the experiment, results for PC are reported, showing, for example, that the phenylene motion is more affected by the strain than the methyl motion.