Filters

2009 - 200912010 - 20151

More filters

20232
Reset filters

Settings

Author: Häußler, Liane × Author: Pötschke, Petra × Subject: A. Carbon nanotubes ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Influence of small scale melt mixing conditions on electrical resistivity of carbon nanotube-polyamide composites
    (Barking : Elsevier, 2009) Krause, Beate; Pötschke, Petra; Häußler, Liane
    Polyamide 6 (PA6) and polyamide 6.6 (PA66) were filled with multiwalled carbon nanotubes (MWNT) using small scale melt mixing under variation of processing conditions, including temperature, rotation speed, and mixing time. In PA66 an electrical percolation threshold of 1 wt% MWNT was found which is lower than that of PA6 at 2.5-4 wt%. In both cases mixing conditions influenced strongly the dispersion and distribution of CNT and the electrical volume resistivity, whereas crystallisation behaviour was only slightly changed. With increasing mixing energy input remaining agglomerates were less in number and smaller, leading to better dispersion. On the other hand, in samples containing 5 wt% MWNT in PA6 electrical volume resistivity showed a minimum at a quite low energy input and then increased considerably with further input of mixing energy. This increase may be related to MWNT breaking during mixing and encapsulation of MWNT by the polyamide chains. © 2008 Elsevier Ltd. All rights reserved.
  • Thumbnail Image
    Item
    Ultralow percolation threshold in polyamide 6.6/MWCNT composites
    (Barking : Elsevier, 2015) Krause, Beate; Boldt, Regine; Häußler, Liane; Pötschke, Petra
    When incorporating multiwalled carbon nanotubes (MWCNTs) synthesised by the aerosol-CVD method using different solvents into polyamide 6.6 (PA66) by melt mixing an ultralow electrical percolation threshold of 0.04. wt.% was found. This very low threshold was assigned to the specific characteristic of the MWCNTs for which a very high aspect ratio, a good dispersability in aqueous surfactant dispersions, and relatively low oxygen content near the surface were measured. The investigation of the composites by transmission electron microscopy on ultrathin cuts as well as by scanning electron microscopy combined with charge contrast imaging on compression moulded plates illustrated a good MWCNT dispersion within the PA66 matrix and that the very high aspect ratio of the nanotubes remained even after melt processing. Additionally, the thermal behaviour of the PA66 composites was investigated using differential scanning calorimetry (DSC) showing that the addition of only 0.05. wt.% MWCNT leads to an increase of the onset crystallization temperature of 11. K.