Rheological properties of glass bead-filled low-density polyethylene composite melts in capillary extrusion

The melt flow of glass bead-filled low-density polyethylene composites in e xtrusion have been observed by using a capillary rheometer to investigate t he effects of temperature, shear rate, and filler content on the rheologica l properties of the melts. The results show that the melt shear flow obeys a power law, and the dependence of the apparent shear viscosity, eta(app), on temperature is in accord with an Arrhenius equation. At the same tempera ture and shear rate, eta(app) increases slightly with increasing the volume fraction of glass beads, but the flow behavior index decreases with increa sing filler content. In addition, the first normal stress difference of the melts linearly increases with increasing wall shear stress. Good agreement is shown with the N-1 calculated with the equation presented in this artic le and the pressured data from the sample melts. (C) 1999 John Wiley & Sons , Inc.