Selective location and double percolation of short carbon fiber filled polymer blends: high-density polyethylene/isotactic polypropylene
The percolation threshold of high-density polyethylene (HDPE)/isotactic polypropylene (iPP) blends filled with vapor-grown carbon fiber (VGCF), 1.25 parts per hundred parts resin (phr) VGCF content, is much lower than those of the individual polymers. SEM micrographs verified that the improvement of electrical conductivity can be attributed to the selective location of VGCF in the HDPE phase. A double percolation is the basic requirement for the conductivity of the composites, i.e., the percolation of carbon fibers in the HDPE phase, and the continuity of this phase in the polymer blends. Short carbon fibers may affect the morphology of the polymer blends.