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Influence of Initial High Shearing on Electrical and Rheological Properties and Formation of Percolating Agglomerates for MWCNT/Epoxy Suspensions
Author(s) -
Schulz Sonja Carolin,
Schlutter Jana,
Bauhofer Wolfgang
Publication year - 2010
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.201000065
Subject(s) - materials science , agglomerate , shear rate , rheology , composite material , shearing (physics) , shear (geology) , epoxy , nanotube , carbon nanotube
We report on shear‐induced nanotube agglomerate formation in low viscous multiwalled carbon nanotube/epoxy suspensions during steady shear rate step tests. A combined setup allows monitoring of the electrical, rheological, and optical properties of the system. High initial shearing was found to be necessary to achieve the insulator‐to‐conductor transition as well as low shear rate viscosity enhancement. Depending on the applied pre‐shear, conductivity improvement of about four orders of magnitude was observed. Different morphologies for shear‐induced agglomerates were detected before and after high shear. The critical minimal shear rate for the system was determined and a simple model using phase separation due to high shear forces is proposed.