Structure and flow behavior of dilute dispersions of carbon nanotubes in polyacrylonitrile-dimethylsulfoxide solution

摘要

Rheological behavior of carbon nanotubes (at the concentration below the percolation threshold) finely dispersed in semidilute polyacrylonitrile-dimethylsulfoxide solution has been studied as a function of the applied pre-shear stress and discussed in view of possible structural changes induced by pre-shearing of the samples. The observed effects have been ascribed to a combination of processes involving alignment and association of the macromolecules as well as orientation and association of carbon nanotubes. The effects caused by the macromolecules alignment and association are mainly observed at low concentration of the filler and at high shear stress, whereas the processes involving carbon nanotubes reorganization are mainly observed at the higher filler content and at lower pre-shear stress. The nanotubes rearrangement under shear has been probed via hyphenated rheology-synchrotron X-ray small-angle scattering measurement.