Composites and Blends Containing Carbon Nano-Structures
The aim of our work is the integration of conductive carbon-nanostructures into thermoplastics using melt processing as well as the characterization of resulting composite properties. Thereby the main focus is pointed on the modification and investigation of electrical, mechanical, rheological, thermal, and tribological properties but also the reaction to fire.
The investigated fillers types are single and multi walled carbon nanotubes (CNT), carbon nano-fibres (CNF), expanded graphite (EG) as well as carbon black (CB). However, the focal point of our work are CNT. The electrical conductivity of such composites results due to the formation of percolated network structures of conductive filler particles in the isolating polymer matrix.
A fundamental part of our work is the characterisation of the relationships between melt processing parameters and filler dispersion and distribution as well the resulting composite properties. Our investigations are based on melt mixing with miniature mixers and laboratory extruders for composite production as well as part shaping like hot pressing, injection moulding, and melt spinning.
The basic principles of network formation, aggregation, orientation or alignment of nanofillers as well as crystalline fractions in partially crystalline polymers control the resulting sample properties dramatically. Furthermore, the structural or morphological as well surface filler characteristics play an important role on the interactions with the matrix like dispersability, connectivity, and thermodynamic stability of the compound.
In polymer blends the effect of conductive filler addition is mainly controlled by the morphology type and filler localisation. If the conductive particles can be successfully concentrated and arranged in the phase boundaries, one can expect that only low filler amounts are necessary for electrical conductivity.
Within in-house cooperations as well as by national and international partners carbon nanofillers are characterized and modified and the processed composites are investigated concerning their spinnability, fracture mechanics, and electrostatic painting behaviour.