Use of carbon nanotube filled polycarbonate in blends with montmorillonite filled polypropylene

Blends were prepared by melt mixing from a conductive polycarbonate composite filled with multiwalled carbon nanotubes (MWNT) and polypropylene containing clay (montmorillonite, MMT). The PC composite, containing 2 wt% MWNT (PC-2NT), was prepared by diluting a PC masterbatch by melt extrusion. The PP nanoclay composite with 3 wt% MMT (PP-3MMT) was produced by melt compounding. Blends were prepared in a small scale Daca Microcompounder over the whole composition range. The aim of the study was to produce conductive blends containing less MWNT than required for the pure PC by using the concept of double percolation through the formation of a co-continuous morphology. The fully co-continuous morphology range was found between 40 and 80 wt% of the filled PC phase. A significant increase in electrical conductivity could be obtained in the composition range starting at 50 wt% (MWNT content about 0.6 vol%). In this range the filled PC forms a continuous phase. Whereas in the blends the MWNT were still dispersed homogeneously within the PC phase, the MMT segregated from the PP towards the blend interface.