Effects of Carbon Fillers on Rheology of Polypropylene-based Resins

Varying amounts of three different carbons ( carbon black, synthetic graphite particles, and carbon nanotubes) are added to polypropylene and the resulting single filler composites are tested for viscosity. In addition, the effects of single fillers and combinations of different carbon fillers are studied via a factorial design. Each single filler and all the combinations of different fillers cause a statistically significant increase in composite viscosity. For synthetic graphite/polypropylene composites, the viscosity increase is due to a volume filling effect. Composites containing carbon black and/or carbon nanotubes show viscosity increases above those containing only synthetic graphite.