Pegel, Sven and Poetschke, Petra and Petzold, Gudrun and Alig, Ingo and Dudkin, Sergej M. and Lellinger, Dirk (2008) Dispersion, agglomeration, and network formation of multiwalled carbon nanotubes in polycarbonate melts. POLYMER, 49 (4). pp. 974-984.
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Three different industrially available multiwalled carbon nanotube (MWNT) materials were directly incorporated into polycarbonate by melt mixing using a small-scale compounder. Despite of similar aspect ratios the electrical percolation behaviour was different. TEM investigations reveal significant differences in the nanotube dispersion which can be attributed to different dispersability of the raw MWNT materials. It is shown that the investigation of the sedimentation behaviour of aqueous MWNT dispersions is a simple method to estimate the nanotube dispersability. The relationships between melt processing conditions and MWNT dispersion and distribution were studied on polycarbonate samples containing 0.875 wt% MWNT prepared by masterbatch dilution. During melt mixing only high shear forces can provide suitable MWNT dispersion because firstly the MWNT disentanglement is facilitated and secondly secondary agglomeration is prevented. At low shear agglomeration of formerly well dispersed MWNT could be observed. During hot pressing the network or MWNT arrangement and the resulting electrical conductivity can be manipulated by the processing conditions like melt temperature and pressing speed. A certain nanotube agglomeration can enhance the development of an electrical percolated network as shown by dielectric spectroscopy. (C) 2007 Elsevier Ltd. All rights reserved.
|Uncontrolled Keywords:||multiwalled carbon nanotubes; polymer composites; melt mixing;Dielectric properties ; Electrical properties ; Experimental study ; Complex permittivity ; Electric resistivity ; Lattice structure ; Morphology ; Dispersion degree ; Property processing relationship ; Structure processing relationship ; Growth from melt ; Mixing ; Manufacturing ; Multiwalled nanotube ; Carbon nanotubes ; Polycarbonate ; Nanocomposite ;|
|Subjects:||Material Science > Functional and hybrid materials|
Material Science > Nanostructured materials
|Deposited By:||Lesley Tobin|
|Deposited On:||04 Dec 2008 16:42|
|Last Modified:||09 Feb 2009 17:29|
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