Thermal conductive polymer-compounds can replace metal, ceramics and conventional plastics for heat-sensitive applications. They are more and more used in various heat-sink applications such as electronics, housings or in automotive parts. The usage of thermally conductive plastics which are injection moldable leads to maximum design flexibility by constructing parts. Furthermore thermal conductive compounds show a lower density and can be much lighter than equivalent components. By variation of fillers and filling content a specific adjustment of thermal properties can be realized. Organic fillers ( e.g. graphite), metallic fillers (e.g. copper) or ceramic fillers (e.g. boron nitride) were used for thermal conductive compounds. The thermal conductivity of commercially available polymer-compounds is usually between 1 W/mK and 20 W/mK what means that they are already 10 to 100 times higher than the conventional unfilled polymer.
During latest development at ZBT the values for thermal conductivity of polymer-compounds have been increased to 30 W/mK. In order to achieve those conductivities, the compound materials generally consist of a polymer, which functions as a binding matrix, and a high content (up to 80 wt.%) of conductive filler material.In various series of investigations the thermal conductivity but also the mechanical properties and the processing by extrusion and injection moulding of the high filled materials were evaluated. An orientation of filler particles by injection molding could be observed.
The experiments presented at the conference “1.Niedersächsisches Symposium Materialtechnik” on 12./13. Februar 2015 in Clausthal-Zellerfeld have shown the potential of this novel class of materials “high thermal conductive polymers”. In order to achieve high thermal conductivities in a polymer a high load of conductive fillers has to be incorporated. Thermal conductivities of up to 30 W/mK could be generated in PP or PA6 what is much higher than actually commercial available compounds. An orientation of filler particles by injection molding could be observed and particular attention has to be paid by the characterisation of parts on that orientation effects.
- Department fuel cells and systems
- Compound technology of ZBT
