Dynamic Electrical and Rheological Percolation in Isotactic Poly(propylene)/Carbon Black Composites

Flocculation of the filler particles in isotactic poly(propylene)/carbon black (iPP/CB) composite melts provides a way to understand electrical and rheological percolation processes. The iPP/CB composites were prepared by mild compounding to ensure a good filler dispersion. Electrical and dynamic rheological characterizations are used to monitor the network formation process in the composite melts. It is found that rheological percolation is more difficult to achieve than the electrical percolation in iPP/CB composites. The discrepancy comes from the different mechanisms for electron transport and stress transfer through the filler network. magnified image