MELT RHEOLOGICAL PROPERTIES OF SILVER-POWDER-FILLED POLYPROPYLENE COMPOSITES

The melt rheological properties of titanate coupling-agent-treated par ticulate silver powder (varying from 0 to 5.6 vol% of Ag) were investi gated. The effect of filler concentration on shear stress, shear rate, melt viscosity, and melt elasticity parameters were determined by usi ng a piston-type capillary rheometer. The study shows that the materia ls follow a power law in viscous behavior over the entire range of she ar rates and temperatures investigated. The melt viscosity decreases w ith filler content up to 4.1% and increases with a further increase in filler content. Interestingly, the viscosity of the composition was l ower than that of unfilled polypropylene. The melt elasticity decrease s with an increase in Ag content in the composites up to 4.1% beyond t hat, it increases. The effect of temperature on the viscoelastic prope rties of filled polypropylene was also investigated.