Melt mixed SWCNT-polypropylene composites with very low electrical percolation

- New SWCNT material Tuball™ from OCSiAl Company was incorporated into polypropylene.
- Melt mixing using a conical twin screw micro-compounder was applied.
- Extremely low electrical percolation was found at 0.1 wt% loading on pressed samples.
- SWCNT macrodispersion is excellent, relatively good nanodispersion into small bundles.

Singlewalled carbon nanotube material of the type TUBALL™ (OCSiAl) was used to prepare composites with polypropylene by melt mixing using a conical twin screw micro-compounder. The compression moulded composites showed electrical percolation between 0.075 and 0.1 wt % and achieved volume resistivity values lower than 1 kOhm-cm already at 0.8 wt % loading. Light microscopy and scanning electron microscopy revealed good distribution and dispersion into small diameter bundles as well as retained high nanotube length. In connection with the very low percolation threshold this indicates that the SWCNT material shows an exceptionally good dispersibility which may be due to relatively high nanotube diameters with a mean value of 1.6 nm. In tensile tests already 0.1 wt % nanotube additions resulted in slight increase in Young's modulus and maximum stress. Tuball™ SWCNT material seems to be very promising for conductivity enhancement.

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