Filters

2009 - 200912010 - 20191

More filters

2021 - 20232
Reset filters

Settings

Author: Krause, Beate × Start date: 2009 × Subject: Thermal properties × WGL Institute: IPF ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Thermal conductivity and electrical resistivity of melt-mixed polypropylene composites containing mixtures of carbon-based fillers
    (Basel : MDPI, 2019) Krause, Beate; Rzeczkowski, Piotr; Pötschke, Petra
    Melt-mixed composites based on polypropylene (PP) with various carbon-based fillers were investigated with regard to their thermal conductivity and electrical resistivity. The composites were filled with up to three fillers by selecting combinations of graphite nanoplatelets (GNP), carbon fibers (CF), carbon nanotubes (CNT), carbon black (CB), and graphite (G) at a constant filler content of 7.5 vol%. The thermal conductivity of PP (0.26 W/(m·K)) improved most using graphite nanoplatelets, whereas electrical resistivity was the lowest when using multiwalled CNT. Synergistic effects could be observed for different filler combinations. The PP composite, which contains a mixture of GNP, CNT, and highly structured CB, simultaneously had high thermal conductivity (0.5 W/(m·K)) and the lowest electrical volume resistivity (4 Ohm·cm).
  • 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.