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Spatial decorrelation of the conductive nanotube network in a polymer melt
Author(s) -
Lellinger Dirk,
Skipa Tetyana,
Böhm Wolfgang,
Alig Ingo
Publication year - 2009
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200982303
Subject(s) - materials science , carbon nanotube , shear (geology) , composite material , polycarbonate , rheometer , conductivity , electrical conductor , nanotube , electrical resistivity and conductivity , chemistry , rheology , electrical engineering , engineering
Time resolved electrical conductivities of a polycarbonate (PC) composite melt filled with multiwalled carbon nanotubes (MWNTs) were measured in a rheometer equipped with ring electrodes. Strain was applied to the melt in trapezoidal shape, i.e., as a first positive shear pulse, followed by a pause of varying duration, and finally a negative shear pulse was applied. It is well known that applying shear to a conductive melt containing nanotubes causes a conductivity decrease due to the destruction of the nanotube network during shear. This effect should be independent on the direction of shear. However, if there was only a short pause between positive and negative shear pulses, one observes an increase of conductivity during the negative shear pulse. For longer pauses, this effect diminishes, and finally, the expected conductivity decrease can be seen. The effect will be explained by the spatial de‐correlation of the nanotubes related to their agglomeration in the melt during the pause. Normalized conductivity of polycarbonate melt with MWNT during the negative shear pulse for varying duration of the pause between positive and negative shear.