Electrically Conductive Carbon Black/Poly(ethylene terephthalate)/polyethylene Microfibrillar Composite: The influence of CaCO3 Nanoparticles

The influence of a complex filler system on the electrical properties of a microfibrillar conductive polymer composite (MCPC)is discussed. By adding insulating filler, nano-CaCO3, to carbon black (CB)-filled MCPC, the morphology of the poly(ethylene terephthalate)(PET)microfibrillar phase was tailored according to the ratio of CB/nano-CaCO3, and so were the electrical properties of MCPC. It was found that nano-CaCO3 did not influence electrical properties in a monotone way. With an increase in nano-CaCO3 content, on one hand, the surface of the microfibrils became smoother, which jeopardized the conductivity of the MCPC. At the same time, the nano-CaCO3 particles substituted for the CB particles on the surface of the microfibrils and further decreased conductivity. On the other hand, longer and better-defined microfibrils could form, which enhanced the conductive network and increased the conductivity of the MCPC. As a result, the percolation threshold changed little compared to the common CB-filled MCPC.